Britain must quit the European Union at the end of October even if that means leaving without a deal, Conservative lawmaker Esther McVey, one of the candidates to succeed Theresa May as prime minister, said on Sunday.

"The 31st October is the key date and we are coming out then and if that means without a deal, then that is what it means," McVey, a pro-Brexit former minister, told Sky News.

"That date is now fixed. We won't be asking for any more extensions, that is part of the corrosive uncertainty that individuals, business and the country don’t want."