Buckingham Palace is in talks with Downing Street about how to keep the Queen out of the looming constitutional crisis over Brexit, The Telegraph can disclose.

Sir Mark Sedwill, the Government’s most senior civil servant, and Edward Young, the Queen’s private secretary, spoke in the past few days on the phone about the increasing calls for Her Majesty to step in.

The conversation was prompted by growing speculation that politicians will try to force the Queen to get involved if Boris Johnson, the Prime Minister, loses a no-confidence vote early next month.

The Labour Party and some Remainer Tory MPs are concerned that Mr Johnson might refuse to quit Downing Street if he loses a vote.

Under the 2011 Fixed Term Parliaments Act, the Queen could be required to ask Jeremy Corbyn or another senior politician to form a Government that can command the confidence of the House of Commons.