A Union Jack Souvenir Shop is seen in east Belfast, Northern Ireland, the United Kingdom, on Oct 19, 2019. British lawmakers on Saturday voted for a key amendment to force British Prime Minister Boris Johnson to seek another Brexit extension from the European Union (EU). Photo:Xinhua

A defiant British government doubled down Sunday, insisting it would leave the EU in 11 days' time despite parliament forcing a reluctant prime minister to request another delay.

In a day of high drama on Saturday, MPs in the House of Commons passed up the chance to decide on the revised withdrawal agreement that Prime Minister Boris Johnson had negotiated with the EU.

That defeat leaves Johnson under mounting pressure to find a way out of paralyzing impasse on when and how Britain would leave the EU bloc after Britons narrowly voted to exit in a 2016 referendum.

Late Saturday, Johnson reluctantly sent European Council President Donald Tusk a letter legally imposed on him by parliament requesting an extension - but refused to sign it.

The Conservative leader sent a second, signed letter insisting he was not seeking an extension to the Brexit deadline, which has already been postponed twice, warning that "a further extension would damage the interests of the UK and our EU partners."

Having failed to back a divorce deal, which Johnson had secured on Thursday, they triggered a law requiring him to write to EU leaders asking to delay Brexit, to avoid the risk that Britain crashes out in less than a fortnight's time.

Senior Cabinet Minister Michael Gove, the government's Brexit planning chief, was nonetheless adamant that Britain would leave the EU on schedule.

"Yes. We are going to leave on October 31. We have the means and the ability to do so," he told Sky News television.

The government will bring forward this week the domestic legislation needed to implement the divorce deal, with a first vote as soon as Tuesday.

Separately, it is seeking a new yes-or-no vote on approving the deal on Monday, although this may fall foul of parliamentary procedure.

"If we get the legislation through then there is no extension. October 31 is within sight," said Gove.

He said it was dangerous to assume that the 27 other EU leaders would grant an extension.

More than three years on from the June 2016 vote to leave the EU, Foreign Secretary Dominic Raab told BBC television that from his conversations with other EU capitals, "they are fed up with this now - and we are fed up with it."