W hether a prime minister misled parliament is a serious matter. The pattern of statements made by Sir Keir Starmer about appointing Lord Mandelson as US ambassador may justify a parliamentary sleaze inquiry. Opposition parties claim that the prime minister misled MPs over the process that led to the peer taking the Washington job. But they would say that, wouldn’t they? More troubling is that in Tuesday’s Commons debate some Labour MPs either abstained or defied the whip and voted to refer the matter to parliament’s privileges committee ahead of next week’s elections. Such rebellion speaks to disillusionment with Sir Keir’s leadership . The prime minister has confessed to making a “ mistake ” in appointing Lord Mandelson despite knowing that he maintained a friendship with Jeffrey Epstein after the financier’s conviction for child sexual abuse offences.…