British MPs have defeated Prime Minister Theresa May’s Brexit plans by giving Parliament the final say on any exit agreement with the European Union.

On Wednesday night in London the parliament voted 309 to 305 in favour of an amendment to demand parliament pass a separate bill to approve any final deal with the EU.

Several MPs from her Conservative Party sided with the opposition to insist that any a deal with the EU require an Act of Parliament before it can take effect — essentially giving MPs a veto on Brexit.

“We are disappointed that Parliament has voted for this amendment despite the strong assurances that we have set out,” a government spokesperson said, expressing concern with the outcome.

“We are as clear as ever that this Bill, and the powers within it, are essential.”

Ms May promised MPs a “meaningful vote” on Britain’s withdrawal agreement, however opponents said it was not enough of a guarantee.

The vote came as an amendment to the EU Withdrawal Bill.

Ms May signalled the fight was far from over, with a spokesman saying the government would explore further changes to the bill.

One option could be attempting to strike out the Tory-backed amendment in further parliamentary stages of the bill’s passage through Parliament.

– with wires