Theresa May's Government will not protect John Bercow from calls for him to resign as Speaker, sources have revealed, as new questions emerge over his financial conduct and impartiality.

Ministers will be free to back a vote of no confidence against the House of Commons chair rather than being asked to abstain by the whips if a motion is brought before MPs.

The decision will increase pressure on Mr Bercow as it emerged a group of Conservative MPs plan to raise the issue of his resignation repeatedly in the House of Commons until his position becomes untenable.