British and European officials are discussing the possibility of extending Article 50 amid fears a Brexit deal will not be completed by March 29, the Telegraph can reveal.

Three separate EU sources confirmed that UK officials had been “putting out feelers” and “testing the waters” on an Article 50 extension, even as the Government said it had no intention of asking to extend the negotiating period.

The discreet diplomatic contacts, described by one source as officials “just doing their homework”, emerged as a minister broke ranks for the first time to raise the possibility of extending the talks.

Margot James, the digital minister, admitted that “we might have to extend Article 50” if Theresa May loses next week’s Parliamentary vote on her Brexit deal.

Downing Street said Ms James was wrong, but her comment sowed suspicion among Brexiteers that ministers were trying to soften up MPs for the possibility that Brexit will have to be delayed.

As tensions in Westminster heightened before next week's vote, a business minister vowed to resign from the Government if it proved necessary to stop no deal.

Leave-supporting Tories fear the party will be punished at the polls - starting with the May local elections - if the Prime Minister breaks her promise to take Britain out of the EU on March 29.