Labour is calling on the Government to set out a timetable for its Brexit plans in the wake of Britain's EU ambassador's sudden resignation.

The party's Brexit spokesman Sir Keir Starmer demanded the Secretary of State answer MPs when Parliament reconvenes on Monday over the decision of Sir Ivan Rogers to quit his post.

Sir Ivan's resignation is likely to be a "significant loss" for Britain and it raises "a number of serious questions" for the Government's preparation for withdrawal negotiations, Sir Keir said.

Prime Minister Theresa May has said she will trigger talks under Article 50 of the EU treaties before the end of March.

In a letter to Secretary of State David Davis, Sir Keir said it was "frankly astonishing" that Sir Ivan had said in his resignation email that he did not yet know the Government's objectives for Brexit.

He added that it is "deeply concerning" that the structure and responsibilities of the negotiating team had not yet been resolved.

"Time is running out," Sir Keir warned. "It is now vital that the Government demonstrates not only that it has a plan but also that it has a clear timetable for publication...

"The best way to clarify these points and wider concerns many people have about this matter would be to make a statement to the House of Commons when Parliament returns on Monday."

Sir Ivan Rogers Credit: European Council

It comes after Sir Ivan criticised the "ill-founded arguments and muddled thinking" of politicians in his resignation letter.

He told his staff in an email that "serious multilateral negotiating experience is in short supply in Whitehall" and reiterated his view that civil servants still do not know the Government's Brexit priorities.

Prominent Leave campaigner Iain Duncan Smith said he was "surprised but not shocked" that Sir Ivan quit.

The Conservative MP said there are "plenty of other really good civil servants, possibly better than him, that will get the job done for government".

He added: "It is damning when our own top people are slamming this Conservative Brexit Government for using ill-founded arguments and muddled thinking."