Theresa May could split from the EU with nothing
British MPs and peers will be able to vote on whether to accept a final Brexit deal - or walk away from the agreement prior to it going before the European Parliament.
The move is being seen as a concession by UK ministers rather than a climbdown, as Prime Minister Theresa May has promised to split from the EU with nothing, rather than accept a poor offer.
The concession is a verbal assurance and not a clause that will be written into the European Union (Notification of Withdrawal) Bill.
But a number of MPs said that a "take it or leave it" vote was not "meaningful" and offered no real choice.
Former shadow chancellor Chris Leslie put forward an amendment requiring parliamentary approval for any deal to be written into the bill.
The Labour backbencher's clause was defeated by 326 votes to 293, a majority of 33, but seven Tory MPs voted against the British government - Ken Clarke, Bob Neill, Andrew Tyrie, Claire Perry, Anna Soubry, Antoinette Sandbach and Heidi Allen.
Six UK Labour MPs voted with the government.
But as the Conservatives' working majority is just 16, if the Tory rebellion grows this could cause headaches for Downing Street further down the line in the Brexit process.
Mrs May is expected by the end of next month to trigger Article 50, when official negotiations can then begin with Brussels over leaving the EU. The talks are due to last two years.
Meanwhile in Scotland, MSPs have voted 90-34 against UK legislation to take Britain out of the EU.
The UK Supreme Court has already ruled the British government does not have to consult the devolved administrations before it starts the formal Brexit process.