What was billed as a ‘Super Saturday’ has turned into a super disappointment for U.K. Prime Minister Boris Johnson as his fellow legislators voted to extend the Brexit withdrawal deadline.

In the first Saturday session of the U.K. Parliament since 1982, legislators voted 322-306 to force Prime Minister Boris Johnson to request an extension from the European Union (E.U.) of the Brexit October 31st deadline.

The House of Commons has approved the amended motion on the new Brexit deal agreed between the UK Government and the EU.

The Government must ask for an extension of Article 50 under the Benn Act and set out how it intends to proceed.

Amended motion: pic.twitter.com/6gMpUOSiBz

— UK House of Commons (@HouseofCommons) October 19, 2019

The vote is a major disappointment for Johnson who, going into Saturday’s session, was riding high on a new deal negotiated with European leaders for the U.K.’s exit from the European Union.

Johnson had been hopeful he would secure the 320 votes needed on Saturday to approve of the new Brexit deal and avoid needing an extension of the upcoming Brexit deadline. However, an amendment proposed by Oliver Letwin, who was expelled from the Conservative Party by Johnson just weeks ago, intended to prevent a “no-deal” Brexit passed by 322 votes, legally requiring Johnson to ask the E.U. for a Brexit extension.

Johnson forced Letwin and 20 other Members of Parliament from the Conservative Party in September for not backing Johnson’s commitment to leave the E.U. with or without a deal on October 31. Letwin supports Brexit, but is unwilling to support a “no-deal exit.”

“My aim is to ensure that Boris’s deal succeeds, but that we have an insurance policy which prevents the UK from crashing out on 31 October by mistake if something goes wrong during the passage of the implementing legislation,” Letwin said in a note explaining his proposal.

As Parliament gathered for debates and the vote on Saturday, close to a million protesters took to London’s streets to march against Brexit and call for a second referendum.

Boris Johnson keeps saying about delivering on the ‘will of the people’.

Here are the people, demanding a #FinalSay on #Brexit:

— People’s Vote UK (@peoplesvote_uk) October 19, 2019

Historic scenes in Parliament Square today as one of the biggest political protests this country has ever seen demanded that the people are given the #FinalSay on Brexit.

Add your voice to the call, sign the letter to the powerful: https://t.co/Hc67Ur2LtG#PeoplesVoteMarch pic.twitter.com/fkmvjR783r

— David Gwyther (@DPGwyther) October 19, 2019

Following the passing of the Letwin Amendment, Johnson sparked worry as he vowed to not request an extension from the E.U. despite being legally required to do so.

“I will not negotiate a delay with the E.U.,” Johnson said to MPs after today’s vote. “And neither does the law compel me to do so.”

However, the Benn Act, which passed in early September, does legally require the U.K. government to ask for an extension from the E.U. by 11 p.m. local time on Saturday. The act, proposed by M.P. Hilary Benn, stipulates that the current Prime Minister of the U.K. asks for an extension of the Brexit withdrawal date if the House of Commons has neither agreed to a “no-deal Brexit” nor a withdrawal plan by October 19. Whether Johnson will follow through and ask for an extension is unknown.

One other possible scenario is Parliament may meet on Monday to vote on the new Brexit withdrawal agreement Johnson recently negotiated with the E.U. After Saturday’s vote, the leader of the House of Commons, Conservative Brexiteer Jacob Rees-Mogg, announced that the government would bring back another “meaningful” vote on Monday.