How do we stop the next David Cameron?

One of the enduring charms of British politics is how slight the pecuniary rewards are for taking up the job of prime minister. American presidents can look forward to stonking great advances on their memoirs. (Barack and Michelle Obama received a joint up-front payment of £47 million from Crown publishing group.) They claim rock-star appearance fees in exchange for a few platitudes to sandalled Silicon Valley execs. (Bill and Hillary Clinton raked in £110 million in speaking fees between 2001 and 2015.) A stint in the White House boosted George H W Bush’s net worth by 475 per cent and Richard Nixon’s by 650 per cent, pocket change compared to Bill Clinton’s 6,150 per cent.

Unlike 1600 Pennsylvania Avenue, no one enters No. 10 Downing Street expecting to leave fantastically wealthier. So there’s something almost admirable about David Cameron managing to parlay six not-terribly-impressive years of government work into an alleged £7 million payday from Greensill Capital.