London CNN  — 

An amendment to delay approval of the UK Prime Minister’s departure deal from the European Union has shaken everything up in Westminster and provided yet another Brexit twist.

Proposed by Oliver Letwin, UK lawmakers voted for the measure that puts the brakes on Boris Johnson’s deal until Parliament passes the legislation required to enact it.

Letwin said his amendment was an “insurance policy” to ensure Britain would not “crash out” of the European Union without a deal on October 31. It passed by 322 votes to 306.

The Letwin amendment, which enjoyed the support of opposition parties, brings the Benn Act into play, requiring Johnson by law to write to the European Commission and request an extension until January 31.

On Twitter the official House of Commons tweeted: “The Government must ask for an extension of Article 50 under the Benn Act and set out how it intends to proceed.”

The Benn Act mandates Johnson to request a Brexit delay by 11 p.m. (6p ET).

However, speaking immediately after the vote Johnson said: “I will not negotiate a delay with the EU, and neither does the law compel me to do so,” he said. “Further delay will be bad for this country.”

What now for Johnson’s deal?

The Letwin amendment does not mean Johnson’s deal is dead. Letwin, an MP who was kicked out of the parliamentary Conservative Party last month when he supported the Benn Act, said he and others would vote for Johnson’s deal with the intention that the UK leaves the EU on October 31.

“When the Prime Minister brings the withdrawal implementation to the House of Commons we will vote for it, we will continue to work for it. We will seek to ensure that it becomes law before 31st October,” he said after his amendment was passed.

Oliver Letwin was expelled from the Conservative party last month when he supported anti-no-deal legislation known as the Benn Act.

But he added that he could now vote for Johnson’s deal without fear of the UK crashing out of the EU.

The leader of the House of Commons, Jacob Rees-Mogg, indicated that the government would bring forward another vote on Johnson’s deal on Monday.

“In the light of today’s decision I should like to inform the house that Monday’s business will now be a debate on the motion relation to Section 13 -1B of the European Union Withdrawal Act 2018 and I shall make further business statement on Monday,” he said, making a point of order.

That section of the withdrawal act legislation provides for a vote in the House of Commons on the result of a negotiated agreement with the EU – in other words, a “meaningful vote.”

It is not yet known whether the EU will grant the UK an extension should Johnson request one. An EU diplomat told CNN that the EU would wait until Tuesday before making a decision.