LONDON: Former British Prime Minister John Major would be willing to go to court to block a new leader from delivering a no-deal Brexit by suspending parliament, saying he would act to prevent the queen from being dragged into a constitutional crisis.

Boris Johnson, the favourite to become the next prime minister, has refused to rule out suspending parliament to ensure Britain leaves the European Union on October 31, with or without a deal.

Major told BBC Radio on Wednesday that Queen Elizabeth would have to approve any request to prorogue parliament.

"In order to close down parliament the prime minister would have to go to her Majesty the Queen and ask for her permission to prorogue," he said. "If her first minister asks for that permission it is almost inconceivable that the queen will do anything other than grant it.

"She is then in the midst of a constitutional controversy that no serious politician should put the queen in the middle of.

"If that were to happen there would be a queue of people who would seek judicial review. I for one would be prepared to go and seek judicial review."