A Government minister insisted Liz Truss was “not under a desk” hiding from MPs after the Prime Minister was urged to quit.

Shouts of “where is she?” and “weak” could be heard in the Commons after Penny Mordaunt deputised for Ms Truss to respond to an urgent question on the Prime Minister’s decision to appoint a new Chancellor.

Commons Leader Ms Mordaunt said: “With apologies to the Leader of the Opposition and the House, the PM is detained on urgent business… and I’m afraid you’ll have to make do with me.”

Labour leader Sir Keir Starmer mocked Ms Truss as he said: “The lady is not for turning – up.

He said the Prime Minister has no mandate, adding: “How can Britain get the stability it needs when all the Government offers is grotesque chaos?

“How can Britain get the stability it needs, when instead of leadership we have this utter vacuum?

Stella Creasy, Labour MP for Walthamstow, said it is the job of the Prime Minister to take big decisions on many issues before adding: “All we know right now is, unless she tells us otherwise, the Prime Minister is cowering under her desk and asking for it all to go away.

“Isn’t it about time she did and let somebody else who can make decisions in the British national interest get in charge instead?”

Ms Mordaunt replied: “Well, the Prime Minister is not under a desk, as the honourable lady says…”

The minister could barely be heard at this point due to laughter and heckling from opposition MPs.

Ms Mordaunt added: “I can assure the House that, with regret, she is not here for a very good reason.”

Earlier, Ms Mordaunt defended the Prime Minister’s decision to appoint Jeremy Hunt as Chancellor in place of Kwasi Kwarteng, saying it was the “right thing to do” and “it took courage”.

She went on to say Sir Keir had not stuck by pledges he made in his own leadership campaign.

SNP deputy Westminster leader Kirsten Oswald accused Ms Truss of “hiding in Downing Street”.

She said: “A Prime Minister terrified to answer for the mess she has made.

“The mess which will cause so much harm to all of our constituents….

“Can the Leader of the House tell us exactly where on earth is the Prime Minister and if she doesn’t even have the backbone to show up here today, is there really any point in her showing up here again? Surely time’s up, she needs to go and let the people decide.”

Prime Minister Liz Truss (Daniel Leal/PA)Prime Minister Liz Truss (Daniel Leal/PA)

Ms Mordaunt later denied claims from Labour MP Andrew Gwynne (Denton and Reddish) that there “has been a coup” in Government, saying the Prime Minister “should be here to defend her decisions today”.

The Commons Leader said: “I don’t think there has been a coup. What I do agree with, with what he said, is these are serious matters for our constituents and I hope that all members will be able to question the Chancellor and get the answers they need for their constituency.”

The Prime Minister later arrived in the Commons ahead of the statement by the new Chancellor Mr Hunt.

MPs had repeatedly asked about the whereabouts of the Prime Minister, with Ms Mordaunt at one stage saying: “I can’t disclose the reasons. I have asked if I can. I am being very genuine with the House on this matter. I hope that she will be able to join us a bit later on this afternoon.”

Labour MP Stephanie Peacock (Barnsley East) joked the Prime Minister was “on the way to the palace”.

But Ms Mordaunt replied: “I would very much like to be able to tell all colleagues what the Prime Minister’s business is today but there are very serious matters as well as economic matters that are in the Prime Minister’s in-tray, and as people will know she comes to this House on a regular basis and she will be here tomorrow but she is not able to be here at this precise moment.”