It seems the prime minister was so desperate to appoint Peter Mandelson as US ambassador he didn’t want to know of any doubts about him, says John Rentoul . He’s gambled, lost – and should pay the price I gnorance is no defence, unless you are a prime minister trying to convince people that you didn’t “knowingly mislead” parliament , which is a resignation matter. The case for Keir Starmer is that he misled the House of Commons – but he didn’t do so knowingly, because he didn’t know that Peter