The British government has been narrowly defeated in a key vote on its Brexit bill after a rebellion by 11 Tory MPs.

In a blow to Prime Minister Theresa May, MPs voted to give Parliament a legal guarantee of a vote on the final Brexit deal struck with Brussels, BBC reported on Wednesday.

The government had argued this would jeopardise its chances of delivering a smooth departure from the European Union (EU).

Despite a last-minute attempt to offer concessions to rebels, an amendment to the bill was backed by 309 to 305.

Ministers said the “minor setback” would not prevent the UK leaving the EU in 2019.

Of the Conservative MPs who voted against the government, eight are former ministers.

One of them, Stephen Hammond, was sacked as Conservative vice chairman in the aftermath of the vote.

“Tonight I put country and constituency before party and voted with my principles to give Parliament a meaningful vote,” he tweeted.

The government said it was “disappointed” at losing – its first defeat on Brexit – despite the “strong assurances” it had offered.

Labour leader Jeremy Corbyn said the defeat was “a humiliating loss of authority” for May on the eve of an EU summit where leaders will discuss Brexit.

It’s the first time that Theresa May has been defeated on her own business in the Commons. She has to front up in Brussels tomorrow with other EU leaders only hours after an embarrassing loss in Parliament.

Beyond the red faces in government tonight, does it really matter? Ministers tonight are divided on that. Two cabinet ministers have told me while it’s disappointing it doesn’t really matter in the big picture.

It’s certainly true that the Tory party is so divided over how we leave the EU that the Parliamentary process was always going to be very, very choppy.

But another minister told me the defeat is “bad for Brexit” and was openly frustrated and worried about their colleagues’ behaviour.

The defeat came after opposition parties joined forces with Conservative rebels during a heated debate in the Chamber on the amendment.

Critics accused those behind the amendment — which was authored by former attorney general Dominic Grieve and championed by other pro-Remain campaigners – of trying to “frustrate” Brexit and tying the government’s hands.

After the result was announced, one of the rebels, former cabinet minister Nicky Morgan, tweeted: “Tonight Parliament took control of the EU Withdrawal process.”

But other Conservative MPs reacted angrily, with one, Nadine Dorries, saying the rebels should be de-selected.

The Tory rebels were Grieve, Heidi Allen, Ken Clarke, Jonathan Djanogly, Stephen Hammond, Sir Oliver Heald, Nicky Morgan, Bob Neill, Antoinette Sandbach, Anna Soubry and Sarah Wollaston.

Another Conservative MP, John Stevenson, abstained by voting in both lobbies.

Two Labour MPs, Frank Field and Kate Hoey, voted with the government.

The UK is due to leave the EU in March 2019, and negotiations are taking place on what their relationship will be like in the future.

The EU Withdrawal Bill is a key part of the government’s exit strategy.