U.K. 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.

Johnson would not step aside if his Brexit proposals were rejected by the European Union, and even if members of the U.K. 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 the U.K. on a course for constitutional showdown with few precedents: Johnson has promised to pull the country out of the EU on Oct. 31 whether the talks succeed, while Parliament has already legislated to prevent him from taking U.K. out of the European bloc without a withdrawal agreement.