The Queen could be asked to block backbench legislation which could frustrate Theresa May's Brexit plans.

A senior Government minister confirmed that one option was for the Queen to be asked not to give royal assent to any backbench legislation drawn up by Tory MPs Dominic Grieve or Nick Boles which is given debating time.

Any veto would be the first time a Monarch has blocked Parliamentary legislation since Queen Anne vetoed the Scottish Militia Act in 1707 and would set the Queen against John Bercow, the Speaker, who has enabled Mr Grieve's attempts to seize control of the Brexit process to go ahead.

The fears were raised in a paper by Sir Stephen Laws QC who said any moves to act without the consent of the Government would risk involving the monarch in "a legislative showdown".

He said it could give rise to a scenario where ministers advise the Queen, the "ultimate referee", to withhold "royal assent" from any Bill, something that has not happened in more than 300 years.

One senior minister told The Telegraph: “I have seen Sir Stephen Laws QC’s view – he is quite right. Dominic Grieve and Co had better think long and hard before potentially involving the Queen in such controversy.