Another minister resigned as the Government narrowly won a vote on its customs bill after Theresa May bowed to pressure from Tory Brexiters.
The prime minister accepted crucial amendments to her Chequers plan for leaving the European Union after she produced proposals that would keep the UK closely tied to Brussels’ rules on goods and food.
Mrs May's decision to capitulate to the Brexiters infuriated Remainers, who sided with Labour on the crucial amendment and, in a vote late on Monday, nearly defeated the Government, who won the vote by 305 votes to 302.
Defence Minister Guto Bebb resigned so he could vote against the Government.
His resignation follows those of Boris Johnson, David Davis and other ministers since the Chequers meeting a little over a week ago.
ITV News Political Editor Robert Peston said that although Mrs May had won the vote, "she really lost".
"This amendment really binds her hands in these crucial Brexit negotiations," Peston said.
"This was not an amendment that at the beginning of the day she wanted to support because it makes it much less likely that the rest of the EU will agree her proposals for a customs plan that will keep the border between Northern Ireland and the Republic open. But because there was a huge rebellion from Brexit supporting Tory MPs she went with this amendment."
The Government's Brexit-linked Taxation (Cross-border Trade) Bill, also known as the customs bill, cleared the Commons after MPs gave it a third reading by 318 votes to 285.
The prime minister was accused of "caving in" to Brexit hardliners ahead of the vote, with one of Conservative MP saying they are now effectively running the country.
Mrs May said the amendments are consistent with her plan.
Pressure on Theresa May was underlined by the disclosure that Brexiteers had set up a Whatsapp group to co-ordinate voting tactics, organised by ex-Brexit minister Steve Baker, who quit over the Chequers plan.
The Daily Telegraph reported more than 100 MPs had joined the group – more than double the 48 needed to submit letters of no confidence in the Prime Minister to force a leadership contest.