LONDON • British Prime Minister Boris Johnson is prepared to challenge Queen Elizabeth II to dismiss him rather than resign as he attempts to push through Brexit by the Oct 31 deadline, the Sunday Times reported, citing senior aides.

Mr Johnson would not step aside if his Brexit proposals were rejected by the European Union, and even if members of the UK Parliament declare no confidence in his government and agree to a caretaker prime minister to replace him, according to the report.

Failure to reach a deal would set Britain on a course for constitutional showdown with few precedents: Mr Johnson has promised to pull Britain out of the EU on Oct 31 whether or not the divorce talks succeed, while Parliament has already legislated to prevent him from taking UK out of the European bloc without a withdrawal agreement.

"Unless the police turn up at the doors of 10 Downing Street with a warrant for the Prime Minister's arrest, he won't be leaving," one senior Conservative said in the report.

The last time a British monarch fired a prime minister was in 1834, it said.