Anglo-French nuclear co-operation, November 1970–April 1971

Heath's initial nuclear decision in October 1970 was to agree a project definition study to investigate Polaris improvement, but his passion was for Anglo-French nuclear co-operation. In November, he established a Cabinet Committee to investigate ‘what the French could hope to gain and what we would be able to give, if the Americans were inclined to be helpful’.Footnote ¹⁴ Heath's first reason for pursuing an option with France was that he sought to strengthen a Western European grouping in the face of the erosion of credibility in America's security guarantee. Parity led some Western Europeans to doubt that America would save Europe if it meant the destruction of her homeland. Secondly, and connected, superpower détente meant that America could disengage from Western Europe, or that Britain might not be able to afford, or be offered, the next generation of nuclear weapons. Thirdly, Heath's favouring of Anglo-French co-operation was part and parcel of his renowned support for British accession to the EC. However, what has been less well appreciated is that it also reflected his rather curious overestimation of Britain's room for manoeuvre in the EC.Footnote ¹⁵ His conception, as Niklas Rossbach has shown, was not that Britain would turn to Europe to the detriment of the Anglo-American relationship. Obviously Europe was going to matter more to Britain in the changed reality of Britain's overseas posture. What Heath sought was more akin to President John F. Kennedy's idea of the ‘twin pillars’, with the European pillar of slightly less weight than the Atlantic one, but propping the Atlantic whole.Footnote ¹⁶ As Heath said to Nixon in December, the offer of nuclear co-operation could be one way to entice France towards a more accommodating stance in NATO.Footnote ¹⁷

By April 1971, the Anglo-French option had quietly slid from Whitehall's main agenda, although Heath continued to broach it in high-level discussions with Nixon and Pompidou until the summer of 1973. Britain's ambassador in Washington, Lord Cromer, interjected that Britain should not approach the Americans about it until they were much more certain of the short- and long-term development of Britain's nuclear policy. In internal studies, the Foreign and Commonwealth Office (FCO) and the Ministry of Defence (MOD) disagreed as to the emphasis they placed on the importance of retaining American assistance. Whereas the FCO were keen to see the development of a political grouping in the EC, perhaps with its own defence, the MOD were anxious not to move away from America and did not think that Europe's political identity would develop so quickly.Footnote ¹⁸ American support, the MOD advised, was far too important to the upkeep of Polaris to jeopardise by too hasty an approach to the French. Moreover, the MOD, who, politically, wanted to sustain and to further Britain's ties with the US, argued that the 1958 Agreement on the Mutual Use of Atomic Energy for Defence Purposes and the 1962 Polaris Sales Agreement meant that Britain had no information, particularly about warhead development, that they were at liberty to pass to the French without first obtaining American agreement.Footnote ¹⁹ On another level, the FCO also advised that they did not want to entangle Britain's EC bid, which now looked promising, with a nuclear offer. If Britain looked to be brokering a deal with the French, particularly with American agreement, over the heads of the rest of the EC, this could jeopardise accession.Footnote ²⁰ Cromer also revealed that the Americans were now planning their own offer of limited nuclear co-operation to France.Footnote ²¹ Added to the fact that it was not at all obvious that the French wanted to collaborate with Britain, the spur to any initiative was blunted by April 1971.

Hence, Heath's initial attitude towards nuclear questions was guided by his political concerns. Britain needed to join the EC and Heath did not want France to be able to argue that Britain was too tied to America. Heath also sought to use nuclear co-operation with France as a means, less to secure entry to the EC, but to prod the EC towards creating a political organisation, and to encourage France back into NATO.

The reasons for upgrade: The Moscow criterion, 1972

Heath's interest in Anglo-French nuclear collaboration was at least in part responsible for a series of studies under the COS. As the COS observed, the long- and short-term prognoses were connected and therefore it was useful to know what either might be.Footnote ²² Furthermore, early in 1972, the COS identified the need for a small increase in funding for the project definition stage of Super Antelope, and ministers would have to clear this. Admiral Peter Hill-Norton, the Chief of Defence Staff (CDS), asked the Defence Policy Staff (DPS) to prepare a submission for ministers, ‘necessary as a vehicle for obtaining the modest increase in financial authority for the Super Antelope project’.Footnote ²³

The resulting paper explicitly aimed to show ‘the advantages of having a deterrent, and the disadvantages of not having one’. As the DPS saw it, the advantages rested on the need to be able to act independently in extremis. The DPS argued that given uncertainty as to whether the Americans could defend Europe in the event of a conventional Soviet attack: ‘the ultimate reason for the possession of strategic nuclear weapons by any Western nation is to ensure its own independence and survival by deterring an attack on itself’.Footnote ²⁴ Hill-Norton added that Britain needed a credible deterrent as a stand-alone power, because Britain could never be absolutely certain that it would be able to rely on America. In the COS meeting on 18 April 1972, he said: ‘the over-riding factor was one of national sovereignty. Did they believe that they could, in the last resort, entirely depend upon others credibly to provide the ultimate counter to the ultimate threat to our national survival?’ He continued:

With the exception of Sir Michael Carver, the Chief of General Staff, the COS agreed with Hill-Norton, but they disputed the extent to which they could present the issue to ministers as one of national survival versus an alliance role. If ministers were given an all or nothing choice of upgrading or allowing the deterrent to wither, then they could choose nothing. Moreover, as the MOD's Chief Scientific Adviser (CSA) Sir Hermann Bondi pointed out, it was difficult for the government to base policy on a rationale that they could not state in public. This rationale was that in order to be credible Britain needed the deterrent to have the capability, by itself, to destroy Moscow.

The COS’ debate revolved around this point. Carver was concerned that too many resources diverted to nuclear power would detract from Britain's conventional capability. He took issue with the need to destroy Moscow and believed that deterrence offered by NATO was enough.Footnote ²⁶ He argued that Britain's weapon could not be thought of as a deterrent, because it would never be used and nobody could realistically believe in its use. Using it would either precipitate an all-out nuclear strike, or Britain would have already been destroyed:

Sir Denis Spotswood, the Chief of the Air Staff, argued that this was not the point. He suggested that what counted was less the actual capability to inflict unacceptable damage, than the ability to instil doubt in the minds of the enemy that it could happen. He pointed out Britain could not have a ‘gold-plated’ deterrent. Britain was not a superpower and had to make do ‘with as much credibility as could be afforded’.Footnote ²⁸ Moreover, Britain's role in Western Europe was essential, and in that sense Britain's possession of a nuclear weapon did reflect a continental commitment. If Britain abandoned the pursuit of independence, then France would be the only independently nuclear-tipped country in Western Europe. Allowing France to assume nuclear leadership would seriously question Britain's prestige: ‘while the possession of a nuclear capability does not make Britain a superpower it does give her a special status among the second class powers, particularly in NATO and we believe will do so in the future enlarged European Community’.Footnote ²⁹ But losing out to France would also undercut Britain's NATO strategy. Bondi argued:

Thus, the Chiefs’ discussion revealed some of the internal disagreements about how Britain's deterrent actually deterred. It was not the first time that this debate had been raised in central government. In 1970, Sir Solly Zuckerman, then the government's Chief Scientific Adviser, had questioned the rationale of the Polaris upgrade. First, he worried – an anxiety partly assuaged by the ABM Treaty of May 1972, which placed limits on the deployment of ABMs – that if the Europeans demanded ABMs of their own it would be the ‘start of a slippery slope of endless proportions’.Footnote ³¹ He also pointed out the implicit assumption, as he saw it, in the ‘Moscow criterion’. His assumptions about the UK's ability to survive a nuclear attack were bleak.Footnote ³² He argued that the Moscow criterion only made sense if the UK might want to strike first. ‘The implication that we would strike first follows the unreal assumption that were we to strike after the Russians, there would still be a London or a Northwood from which to issue orders. Is it politically conceivable that we would in fact start an all-out nuclear exchange?’ He argued that Britain could rely on a NATO role, with the ability to strike cities other than Moscow.Footnote ³³

The Cabinet Secretary, Sir Burke Trend, had agreed with Zuckerman when Zuckerman wanted to push for further studies of Anglo-French nuclear co-operation. However, Trend was very clear that it was not a good idea for the government to opt to do nothing. As Cabinet Secretary, Trend was crucial in articulating the concerns of the security establishment to central government. Trend was intensely political, a master of clarifying the political principles at stake and voicing them accordingly. Based on the COS study, Peter Carrington, the Minister for Defence, wrote to Heath on 11 April to update him on the options. As he guided Heath through Carrington's submission, Trend elected to sharpen the distinction the COS had tried to blur: the choice between upgrade or not. Trend argued: ‘unless we are prepared to abandon an independent nuclear capability of our own, we shall soon have to decide – as you know – whether to improve the Polaris missile by the device comprised under the code word Super Antelope or to replace it by the more advanced Poseidon missile’. Whichever Britain chose ultimately, they had to authorise the immediate increase of up to £9m in funding for Super Antelope's project definition stage.Footnote ³⁴

The Chancellor, Anthony Barber, approved the additional increase, but also signalled concern at the spiralling future costs of the defence budget. He told Heath he was ‘instinctively sympathetic’ to the maintenance of an appropriate level of destruction but also argued that it ‘should not be taken for granted’.Footnote ³⁵ Trend countered: ‘in one interpretation, those words could mean that we should so limit our future activity in this respect, primarily for reasons of cost, that our independent deterrent should become progressively less credible until it became wholly incredible’. Trend's concern was the security of the country, as he saw it, but he voiced the argument as a political one. Britain was not entering the nuclear race, but could not afford to lose the nuclear capability it already had. He also made a sharp party political point, a jibe at Wilson's difficulties with party opinion on nuclear questions, that the Conservatives should be more attuned to defending the realm than Labour:

Consequently, there was no question of principle. Any debates about the upgrade were debates of degree. Should Britain opt to buy Poseidon, or a variant of it, or proceed with Super Antelope? Trend accepted fully that in the last resort, Britain had to be able to stand alone. His argument was embedded in a deterrence frame of mind. Britain was a small island, it was vulnerable, and only the capacity to hit where it hurt would deter.

However, there was some arbitrariness about exactly how much destruction Britain needed. When, in 1962, the JIC put the case that destroying five cities would suffice, rather than the forty of a COS paper in 1957, the circumspection in their judgement was clear.Footnote ³⁷ Bombing forty cities was ‘quite unacceptable’ to the Soviet Union, as it would ensure that they could not recover ahead of the United States following nuclear war. Neutralising twenty would be an ‘unacceptable blow’. Of the capacity to erase the top five, the JIC admitted that they ‘cannot give a clear-cut answer’, but that ‘it would not be unreasonable to say that the Soviet leaders would consider that the certain destruction of their five largest cities would put them at an unacceptable disadvantage in relation to the United States’.Footnote ³⁸ In 1972, based on the psychological importance of Moscow to the Soviets, the JIC argued it was sufficient to concentrate resources on the ability only to destroy the Soviet capital.Footnote ³⁹ Hill-Norton summarised: ‘Moscow is uniquely important in Soviet minds as the capital, the administrative focal point and the largest centre of population. Its destruction while not sufficient to cause a total breakdown of the governmental structure would cause considerable disruption and might threaten the political cohesion of the country’.Footnote ⁴⁰

The conclusion of the ABM Treaty, which permitted the Soviet Union to concentrate ABMs around Moscow and one other location, strengthened this rationale. It demonstrated the importance the Soviets attached to Moscow, and the Deputy Chief of Defence Staff concluded that ‘whatever the specific importance of Moscow, a UK strategic deterrent must have the capacity to penetrate the appropriate Russian ABM system’.Footnote ⁴¹ Moreover, the intelligence community and defence establishment feared that as an all-out attack by the United States on the Soviet Union could overwhelm ABM defence, the Soviets could see the significance of ABMs as eliminating small nuclear forces. If the Russians knew that the British were targeting cities other than Moscow, it could lead them to discount the British deterrent.Footnote ⁴² If the Soviets chose to concentrate on picking off small nuclear forces, they could extend ABMs to targets other than Moscow, effectively rendering Britain's force obsolete. Hill-Norton concluded:

The discussions showed complexities in Britain's strategic posture. There were uncertainties about the future development of Soviet ABMs, uncertainties about what exactly would deter the Soviet Union and uncertainties about how precisely the deterrent did its job of preventing an attack on the UK. Was it the fact of unacceptable destruction, or the possibility that this might happen that mattered? Would a NATO deterrent be enough? These were questions for which there could not be one cast-iron answer. There were limits on what anyone could divine about Soviet intentions.Footnote ⁴⁴ British war planning was based upon the scenario of a gradual escalation of tensions, but there were obvious boundaries about what could be established about the inception of any nuclear exchange.Footnote ⁴⁵ Perhaps understandably, given their roles, the responses of the JIC and the COS to these necessary limitations were to assume the future extension of dangers. The JIC presumed that the Soviets might seek to extend ABM coverage and might come totally to discount the British deterrent. They regarded the Soviet threat as the only real threat, but, as they saw it, they had to guard against British weakness. Only the maintenance of a credible independent deterrent would counter these risks.

The perceived strategic need for an independent nuclear weapon, that in extremis Britain could use itself, resulted from an understanding about how much destruction Britain needed in order to be able to deter the Soviet Union from attacking it. However, the argument was also political, particularly in the hands of Trend, who was a vital link conveying the COS and JIC arguments to Heath.

Trend's arguments were rooted in tradition, in a sense of Britain's proper place in world politics. As Peter Hennessy shows, this was ‘the “standing alone” contingency, the memory of summer–autumn 1940 which Sir Frank Cooper, another long time MOD nuclear insider, reckoned always played powerfully on prime ministers’ minds’.Footnote ⁴⁶ ‘Standing alone’ incorporated many ideas. It was not just about prestige, as the idea of prestige was entangled with an understanding of Britain's cold war role. Britain's deterrent was a core part of the Anglo-American relationship, but it was also a hedge against American unreliability, and it reflected Britain's responsibility for the maintenance of European peace by balancing any potential German resurgence against the uncertainty, and weakness, of France. British sovereignty, and, as Trend implied, the practice of statecraft by a Conservative prime minister, was bound up with these particular ideas.Footnote ⁴⁷ To be truly sovereign, and thus to be able to fulfil its particular, historically informed role, Britain needed to be thought to have the capacity to act alone.

Hybrid/STAG, November 1972

Since the demise of the Anglo-French nuclear option, Heath had not clearly articulated his position on British nuclear weapons. However, by November 1972, if not before, it was evident that he accepted the need to upgrade. An MOD paper, presented to ministers in November 1972, argued that the options were to proceed with Super Antelope; or to go for a ‘UK Poseidon’, which involved buying Poseidon C3 missiles, including a MIRV capability, but using British warheads. The third, new option was Hybrid, rebranded STAG by Heath in December.Footnote ⁴⁸ Hybrid/STAG was to replace Polaris with Poseidon C3 and use Super Antelope to improve both the warheads and the re-entry system.Footnote ⁴⁹ This was the option Carrington now recommended.

The project definition stage of Super Antelope was proceeding satisfactorily, and it was the preferred option of Bondi, the MOD's Chief Scientific Adviser, as well as of the Atomic Weapons Research Establishment (AWRE). The Navy, however, favoured Poseidon. Partly, this was because they wanted commonality with American hardware. As the Americans moved to Poseidon, the Navy feared that if Britain fell behind they would not be able to catch up again later. It was also because Poseidon was operationally better. It had better range, and better capability should the Soviets develop the more sophisticated terminal ABM defence.Footnote ⁵⁰ Poseidon, however, posed political problems and was more expensive than Super Antelope in the short term. President Nixon was personally supportive of selling Poseidon to the UK, but in the climate of the Strategic Arms Limitation Treaty (SALT), Congressional opinion could resist it.Footnote ⁵¹ For Britain, the purchase of Poseidon would underscore British links to America in a more obvious way than the continuation of Super Antelope and could choke off any possibility of Anglo-French nuclear co-operation on a successor system.

The MOD recommended Hybrid/STAG. Trend, aware of the internal divisions within the MOD, was suspicious about this. Hybrid/STAG had not been investigated as thoroughly. He commented that the Navy had always wanted Poseidon, and may have conceded in order to ensure access to some US hardware, if not all: ‘Is one entitled to smell a rather uneasy compromise here, within the MOD itself?’Footnote ⁵² Trend counselled Heath that the government should not yet give up the possibility of the fully MIRVed Poseidon. With the presidential elections in the US expected to return Nixon with a large majority, he could now be willing to offer it.

The ministers present at the meeting – Heath, Carrington, the Foreign Secretary, Alec Douglas-Home and Barber – agreed to pursue Hybrid/STAG. Carrington dispensed with UK-Poseidon on political grounds. The US did not want to sell it, it was expensive, it would prevent a British research effort in re-entry vehicles and it would annoy the French. Compared to Super Antelope, Hybrid/STAG had better range and development potential against terminal defence. Carrington also argued that the costs of the upkeep of Polaris would rise dramatically after 1983, when it went out of service in the US. Consequently, it would be difficult to maintain Super Antelope in service much beyond 1985, whereas Hybrid/STAG would be operational until the mid-1990s. The overall cost of Hybrid/STAG would be less than Super Antelope, although over the next ten years it would be more expensive.Footnote ⁵³

Hybrid/STAG represented an internal compromise in the MOD, and it combined the operational benefits of Poseidon with the political balance the government sought between America and Europe. Despite the inauspicious outlook for Anglo-French co-operation, Carrington recommended a renewed effort to create a European defence organisation, linked to NATO but outside NATO, that could draw France more closely back into integrated Western European defence. He was concerned about pressures to reduce expenditure on conventional defence and anxious that détente might normalise Soviet power and allow the Soviets to pick the Western Europeans apart.Footnote ⁵⁴ Carrington had told the Conservative Party Conference that British entry into the EC could galvanise opinion behind the creation of a European political grouping.Footnote ⁵⁵ He knew that the chances of success were limited, but suggested the enticement of nuclear collaboration could persuade France to join such a grouping.Footnote ⁵⁶ Thus, Heath consented to seek Nixon's views on selling Poseidon, and to request further investigation of the risks of Hybrid/STAG. He suggested that Carrington should keep the French defence minister, Michel Debré, informed, to avoid appearing to present the French with a fait accompli. There was still time for further consideration of options for the nuclear force that would follow Polaris/Poseidon.Footnote ⁵⁷

Hence, the political concerns that governed Heath's approach to the nuclear upgrade in 1970 and 1971 still counted. Britain signed the Treaty of Accession with the EC in January 1972, and the government was keen to make a good impression at the inaugural summit of the Nine in Paris in October 1972, a summit that many saw as the inception of a political European organisation.Footnote ⁵⁸ Heath wanted to leave open the possibility of Anglo-French nuclear co-operation on a successor system, despite the unlikely prospect of success. He wanted to align the EC with the United States in a more equally weighted relationship, and did not want a too obvious tie between the US and Britain to jeopardise this. Hybrid-STAG appeared to fulfil Britain's military and political objectives.

Option M, February–July 1973

When Heath met Nixon in February 1973, the Americans made a new offer. There were considerable technological difficulties involved in de-MIRVing the Poseidon missile in order for it to take STAG. Consequently, Defence Secretary James Schlesinger offered Option M. This was that Britain would buy the Poseidon C3 missile, and would also buy the non-nuclear parts of the Mark III re-entry vehicle and warhead. For the nuclear parts of the warhead, the US would supply designs and the British would manufacture them in the UK.Footnote ⁵⁹ The Mark III warhead was lighter and much faster, and more could be carried on an individual missile; but because the British would be reliant upon American designs, it would underscore British dependence upon America.Footnote ⁶⁰ While technical difficulties with Hybrid/STAG were one reason for the shift, another was that Super Antelope technology had less development potential against terminal defence.

The Americans had picked up a comment on the fringes of SALT that the Soviets might be able to deploy terminal ABM defences around Moscow much more quickly than anticipated.Footnote ⁶¹ Trend queried this, but if it were correct, the technology of Super Antelope could become obsolete in three or four years.Footnote ⁶² Victor Macklen, the Deputy Chief Scientific Adviser at the MOD, advised caution. He suggested that the Russians could have said that they had a sprint type terminal defence on the drawing board for any number of reasons. He saw no case to revise the earlier judgement that there would be time to develop STAG to cope with advances in Russian defence. Moreover, ‘provided we kept the details of our actual improvement secret the Russians could not be sure. . .and absolute certainty to the defence is quite a different calculation from absolute certainty for the attacker’.Footnote ⁶³

Option M crystallised the splits in the MOD as to how to proceed. The Navy wanted Option M for its operational advantages and commonality with US hardware. Hill-Norton recommended an immediate decision in favour, in order to strengthen the President's hand in securing the Presidential determination necessary to release information about it.Footnote ⁶⁴ Bondi supported Super Antelope. He disputed whether the cost of the upkeep of Polaris would be prohibitive after it went out of service in the US.Footnote ⁶⁵ British independence in warhead research would decline and Option M illustrated British reliance upon the Americans.Footnote ⁶⁶

These political doubts worried central government. Cromer remarked that as the White House had gone as far as to offer it, if Britain did not accept it, ‘the Americans are likely to conclude that we and the French would prefer some kind of European nuclear wilderness to the Atlantic Alliance’.Footnote ⁶⁷ Trend speculated that one American motivation could be to ensure British subservience: ‘we shall gradually cease to be an independent competitor in this particular technological race’.Footnote ⁶⁸ Option M would also reduce any freedom of manoeuvre Britain had to court the French. The US would be unlikely to wish to supply Poseidon technology to France to facilitate a trilateral agreement. Trend noted that the French Foreign Minister, Michel Jobert, commented: ‘a decision by us to buy Poseidon would postpone Anglo-French co-operation into the next century’.Footnote ⁶⁹ There was also the rather more practical problem that Nixon would have to request a Presidential determination in order to release information to Britain about Option M. The Presidential determination would require the consent of the Joint Committee on Atomic Energy (JCAE). It could take time and the determination would also make the option public.Footnote ⁷⁰

In April, Carrington remained non-committal, but the government felt that Heath could not decisively tell Nixon Britain wanted Option M.Footnote ⁷¹ Even though the diplomacy connected with the Year of Europe was beginning to get acrimonious, the British continued to talk to their American counterparts about the possibilities.Footnote ⁷² Kissinger explained to Trend that he and Nixon wanted to help Britain's nuclear deterrent as ‘reinsurance’ against loss of nerve on the part of a future American Presidency. If American administrations were unable to sustain America's commitment to Western Europe, then the Soviets would have to bank on being able to eliminate more than one nuclear rival.Footnote ⁷³ In June, developments in SALT led the British to wonder if Nixon would sell the fully MIRVed Poseidon. This would circumvent the technical risks involved in de-MIRVing the Poseidon for sale for Option M.Footnote ⁷⁴ However, as the fall-out of Watergate began to tighten around the President, Cromer indicated that the President would be ‘mighty relieved’ if Heath did not press for it. ‘Congressional uproar was certain’ and the President did not want to face this in his ‘present weakened position’.Footnote ⁷⁵

In addition to the political difficulties, the main constraining factor on a British decision was cost. Growth and inflation in the UK accelerated and expenditure cuts became vital. In May 1973 Barber announced immediate savings of £500m.Footnote ⁷⁶ As part of this drive, Carrington conceded that the money for the nuclear upgrade would no longer come from reserved funds, but would be included within the defence budget. Consequently, an expensive upgrade could mean reductions in conventional forces.Footnote ⁷⁷ Cost-wise, Option M was more expensive in the critical period of the Long-Term Costings (LTC): the excess in 1973–8 over the base cost of maintaining unimproved Polaris was £193m as compared to Super Antelope's £72m. Carrington also speculated that a new administration ‘of a different political complexion’ might not be able or willing to sustain Option M.Footnote ⁷⁸

By July, the government conceded that the French were only thinking ‘very long term’ about collaboration.Footnote ⁷⁹ Heath met Pompidou at the end of May, and tentative suggestions for an official study into subsequent collaboration led nowhere. Pompidou subsequently agreed with Nixon at Reykjavik to explore American–French co-operation, and this reduced further the already limited attraction of any agreement with Britain. The removal of the French option, however, did not lead the government to a more insistent tilt towards the Americans. Carrington recorded that the balance of opinion between options was very fine. Did the undoubted technical advantages of Option M outweigh the financial disadvantages and the political concerns?Footnote ⁸⁰ Trend was in favour of Option M: ‘if you believe, as I do, that the critical consideration in exercise of choice is the ultimate safety of this country, Option M is best’. Britain was dependent upon America, and it might as well accept this fact while the offer was good.Footnote ⁸¹ Ministers deferred a decision. Heath said that the problems were complicated and they would try to take a decision soon.Footnote ⁸²

The offer of Option M meant that nuclear ties with America, and the question of whether to buy Poseidon, assumed a more central place in British deliberations. Thus, although Anglo-American relations worsened after Kissinger launched the Year of Europe, discussions between the two administrations about Option M and Poseidon increased. At the same time, the tensions in Heath's broader political strategy became more acute. The Year of Europe made it virtually impossible for Heath to be able to lean towards France while sustaining cordial relations with Nixon and Kissinger.Footnote ⁸³ After May 1973, it was clear that Pompidou did not want to co-operate with Britain in matters nuclear. Added to concerns about cost, and internal disagreements about whether Britain needed Option M or whether Super Antelope was better, Britain's policy reached an impasse. The issues were complex and could not yet be resolved.

Super Antelope, August–October 1973

In the final three months before the decision was taken, the government's primary concern was cost. Early in September, a statement that the Russians had acquired MIRVs led to more conjecture that the US might be willing to supply Britain with a fully MIRVed Poseidon. Further soundings reiterated the significance of Watergate: the chances were 50–50, or at best ‘60–40’.Footnote ⁸⁴ The burdens of government were also felt in Britain, as Carrington's gloomy rejoinder about what a Labour administration would do to the deterrent demonstrated. A private meeting with the miners’ leader Joe Gormley in July indicated that the miners might not be content with the final phase of Heath's pay policy, due to be implemented in October.Footnote ⁸⁵ Heath did not feel secure, fearing a determined effort by the Communist Party of Great Britain to unseat the top of political authority in Britain.Footnote ⁸⁶ In August, he commented to Trend that there were ‘present attempts to create a Watergate atmosphere in this country’.Footnote ⁸⁷

Thus, in the context of the need to reduce public expenditure by a government that felt fragile, the cost of the nuclear options was politically sensitive. On 12 September, ministers met again and Heath indicated that while they would release funds for the continuation of Super Antelope, they needed urgently to resolve the implications of the Polaris upgrade for the defence budget overall.Footnote ⁸⁸ Barber was adamant that it was necessary progressively to reduce the proportion of expenditure devoted to defence. Currently it stood at 5.5% of GNP, the highest level in NATO, although Britain was only the eleventh wealthiest country in NATO. France devoted 4.2% of GNP and Germany 3.8%. Barber wanted to reduce Britain's proportion to 4.5% by 1977/8. Failure to do so, he argued, could be dire: ‘it would undermine our industrial and economic capacity to play our part in the building of Europe’.Footnote ⁸⁹ Carrington countered that to do so would renege on ‘everything we have fought for over the last three years’, and would seriously curtail Britain's ability to maintain a role in NATO and conventional force levels in Western Europe.Footnote ⁹⁰

A further factor was that there was no compelling public case to justify the purchase of Poseidon. There was no public information about the upgrade programme, and the Labour opposition would surely have made political capital from an announcement to spend money on Poseidon. Following a motion from Gormley at the 1972 Labour Party conference to demand the removal of American nuclear bases from Britain, Labour's National Executive Committee had conceded that Labour would seek the removal of the base at Holy Loch.Footnote ⁹¹ In August, the House of Commons Expenditure Committee published a report. Without access to the same intelligence reports as the government, it assessed that Polaris (unimproved) had an 81% chance of hitting its targets, and hence, that it was ‘adequate’ to keep Polaris in service. The purchase of a MIRVed Poseidon or the pursuit of a MIRV programme in the UK would constitute an ‘expensive luxury’.Footnote ⁹² Arthur Hockaday, the Assistant Under-Secretary of State in the MOD, commented that the report placed the ‘onus of proof that it would be worthwhile for Britain to acquire Poseidon . . . on those who might wish to make that change’.Footnote ⁹³

By the end of October, the financial considerations, and the anxieties about Watergate's effect on the President, overrode the technical case for Option M. Sir John Hunt, who took over as Cabinet Secretary following Trend's retirement, recorded ‘grave doubts’ that Nixon would be able to secure Congressional agreement for the sale of the de-MIRVed Poseidon.Footnote ⁹⁴ Although there were risks of the enhanced cost of Polaris once the Americans stopped using it, there were also doubts about the cost of the dispensing mechanism for Option M.Footnote ⁹⁵ Finally, ‘there was no change in the technological considerations, but the financial situation was more serious’. The Middle East War and the rise in the cost of oil stoked inflation and strengthened the hands of the miners, who were unhappy about the pay deal on offer. With more strikes on the horizon, and with the urgent need to reduce public spending, it mattered that Option M cost more than Super Antelope in the spending projected between 1975 and 1978, even though the differences were not that great.Footnote ⁹⁶

In their meeting on 30 October, Heath, Carrington, Douglas Home and Barber agreed that Super Antelope was adequate for now. It involved fewer risks – so they thought – and it demanded less initial financial outlay and less dollar expenditure. Britain's independent research effort would be sustained and, while ministers felt that this would be more credible if they could reach an agreement with the French, they also noted that American agreements meant that Britain could not pass warhead information to France anyway.Footnote ⁹⁷ Hunt suggested a parliamentary announcement to Heath. However, Kissinger's ‘tantrums’ over the Year of Europe led Hunt to urge that Britain should not yet reveal its decision to the Americans and consequently, an announcement to the House was delayed.Footnote ⁹⁸ Hunt raised it again with Heath in February, suggesting that the planned statement in the Defence White Paper should now be withheld until after the February 1974 election.Footnote ⁹⁹ It was left to the Labour government Carrington had anticipated to agree to continue with Super Antelope, but also to evade the declaration of the upgrade programme to the House of Commons.