Sir Keir Starmer is facing mounting calls to quit after it was revealed that Peter Mandelson was made US ambassador despite failing security vetting.

Foreign Office officials pushed the controversial appointment through regardless, and the Prime Minister now faces the allegation that he lied to Parliament.

Sir Keir has insisted on numerous occasions that the disgraced Labour peer had been properly cleared to take up Britain's most important diplomatic post.

He was told by opposition leaders to stand down if he is found to have misled MPs, while some of his own backbenchers admitted his position was untenable.

Downing Street claims the Foreign Office acted alone in granting Mandelson the developed vetting (DV) status needed to take up his job in Washington against the advice of internal security experts. An investigation has been launched by No.10.

The Foreign Office's top civil servant Sir Olly Robbins has been effectively sacked after the revelation that officials took the rare step of overruling the recommendation. 

Now it's time to have your say – do you think Sir Keir should resign?

In yesterday's poll, Mail readers were asked: 'Was the US-Israeli war on Iran a 'mistake', as Reeves claims?' Out of more than 5,000 votes, 54 per cent of you said 'yes' and 46 per cent said 'no'.