The last of our three biographical chapters focuses on Boris Johnson, Britain’s former prime minister. Throughout his political career Johnson had a reputation for telling untruths, and he has had long-standing conflicts with the UKSA. By examining these conflicts, we can see how the UKSA developed its strategies for successfully countering statistical manipulation. We see Johnson and the UKSA in a battle for ‘ethos’ or public reputation. Among the early controversies which we discuss are Johnson misusing statistics to claim low rates of offending and Johnson’s accusations that the UKSA was biased against him. We also look at his much reported claims about the money that Britain would save from leaving the European Community. The UKSA also pointed out Johnson’s misuse of statistics during his premiership: for instance, only considering a proportion of total crimes when suggesting that all crime had fallen; or only considering a proportion of the unemployed to say that all unemployment had fallen. Johnson, however, seemed the loser in the battle for ethos. When the press reported these conflicts with the UKAS, it regularly sided with the UKSA, which it called ‘the national statistics watchdog’. Even the right-wing, Johnson-supporting newspapers have backed the UKSA, thereby confirming the Authority’s strategic approach.