Jeremy Corbyn has been criticised by Remain supporters inside and outside Labour after saying his party would go ahead with Brexit if it won a snap general election in the new year.
The opposition leader used an interview with the Guardian to also say that he would recommend the party advocate Brexit if there was a second referendum as he hit out at EU laws on state aid which he said blocked investment.
But his remarks were attacked by Labour MPs who believe he should swing the party behind a second referendum that would give people a chance to stay in the EU.
Labour's former shadow business minister Chuka Umunna said the interview was "deeply depressing and disappointing".
Writing on Facebook he said: "Brexit is essentially a project of the hard right of British politics who want to turn Britain into a lightly regulated, offshore tax haven for the super rich, devoid of proper protections for workers, and one which seeks to dump the blame for the UK's problems on immigrants.
"Labour should stop pretending there is 'good' Brexit deal and we should certainly not be sponsoring this project because Brexit is the problem - it solves nothing."
'A matter for the party to decide'
Mr Corbyn told the Guardian that if there was a general election in the new year sparked by the parliamentary deadlock over Mrs May's Withdrawal Agreement, he would "go back and negotiate (with the EU) and see what the timetable would be".
Asked about a second referendum, which is favoured by many of his MPs and Labour supporters, he added: "It would be a matter for the party to decide what the policy would be; but my proposal at this moment is that we go forward, trying to get a customs union with the EU in which we would be able to be proper trading partners."
Labour passed a motion at its party conference in Liverpool in September that it would seek a general election as its first choice, but left open the option of supporting a second referendum.
Mr Corbyn and other opposition frontbenchers have claimed that were Labour to replace Mrs May's Government by some means, they would be able to go back to Brussels to renegotiate her deal.
'This 11th hour'
But Ilford North Labour MP Wes Streeting, a critic of Mr Corbyn, attacked his remarks, saying: "Why peddle this myth that Labour would be able to renegotiate a Brexit deal at this 11th hour?
"How would Labour's Brexit be any better than remaining in the EU?
"Our members and voters are overwhelmingly pro-European. This lets them, and our country, down."
Our Future, Our Choice, an anti-Brexit youth campaign group wrote on twitter that backing Brexit would be a “huge betrayal”.
They said: “Labour backing Brexit in a General Election would be a huge betrayal of young people. Don’t do it.”
The SNP also attacked Mr Corbyn, with Westminster leader Ian Blackford calling him "the midwife to the delivery of the Tory's Brexit plans".
Mr Blackford said: "Jeremy Corbyn has finally come off the fence he's been sat on for the past two years.
"But unfathomably he's come down on the same side as Theresa May.
"The Labour party is incapable of providing opposition to the worst UK government that most people can remember."