Three Labour frontbenchers have been sacked for defying Jeremy Corbyn and backing a call for the UK to stay in the single market after Brexit.
Ruth Cadbury, Catherine West and Andy Slaughter had supported Chuka Umunna’s amendment to the Queen’s Speech.
Staying in the single market is not Labour policy and Mr Corbyn had ordered his MPs to abstain – 50 rebelled.
His deputy Tom Watson said he was disappointed with Mr Umunna for trying to “divide” Labour MPs with the vote.
Mr Watson told the BBC he was “obviously a little disappointed that my colleague Chuka Umunna felt that he needed to move an amendment”.
He added: “I just felt that given we’d come out of the general election with such an unexpected result, and there’s a real euphoria, to try and divide Labour MPs a week and a half in was a little disappointing.
“But, you know, we’re still buzzing, we still want to hold the government to account, we’ll get over it and move on.”
Forty nine Labour MPs voted for the amendment while a 50th – Heidi Alexander – acted as a teller, one of the MPs who count the votes.
Daniel Zeichner quit as shadow transport minister to take part in the vote.
He said in a statement he was resigning “with great regret” but added: “My position on Europe has always been clear. I am a passionate pro-European and a straight-forward politician.”
Mr Umunna’s amendment was defeated by 322 votes to 101, majority 221, during a series of final votes on the government’s Queen’s Speech.
Among the Labour MPs who backed it was Stella Creasy, who appeared on the BBC’s Question Time on Thursday.
She said she had done so because she wanted single market membership to be “part of the [Brexit] negotiations… because the economic and social cost of these things is going to be horrific” – arguing 650,000 jobs in London alone depended on the single market.
“I want all of these options on the table,” she said, arguing there were “101 different combinations” that could see the UK leave the EU while remaining in the single market.
But her fellow panellist, International Trade Secretary Liam Fox said: “The people who say: ‘We want to stay in the single market, we want to stay in the customs union but we really will still respect the will of the British people’ – it’s not true.
“They’ve tried to frustrate the will of the British people.”
Mr Corbyn has committed to leaving the single market after Brexit. A Labour amendment proposed by shadow chancellor John McDonnell was defeated by 323 to 297.
It called for Brexit to deliver the “exact same benefits” as the EU single market and customs union, as well as scrapping tuition fees, increasing public spending and ending the public sector pay cap.
Labour MP Hilary Benn told the BBC: “I think we recognise that membership of the single market creates a difficulty because… you can’t control free movement if you are in the single market.
“The policy on which we fought the election was to say that we wish to retain the benefits of the single market and the customs union.
“I think if the reference to the single market had not been in Chuka’s amendment then you would’ve seen a different outcome.”
Unison’s general secretary Dave Prentis was very critical of Mr Umunna’s amendment, saying it was “totally inappropriate for Labour MPs to create a split over Europe” and “utterly self-defeating to become bogged down in the worst kind of gesture politics”.
The government survived its first major Parliamentary test when MPs voted 323 to 309 in favour of the Queen’s Speech – the government’s package of legislation – which was stripped back after the Tories lost their Commons majority.
The Democratic Unionist Party’s 10 MPs had agreed to support the measures as part of a deal with the Tories.