Prime MinisterBoris Johnson on Wednesday told a febrile UK parliament that he would leave office with his “head held high” despite the downfall of his scandal-hit leadership. Labour leaderKeir Starmer took aim at his outgoing foe during the weekly Prime Minister’s Questions session, calling him “totally deluded to the bitter end”, raising cheers from the opposition benches. In a sign of things to come, Starmer also set his sights on those Tory MPs battling to become prime minister, including on the complicated tax affairs of wealthy frontrunner Rishi Sunak. The session began with a furious Spe…