Labour leader Jeremy Corbyn said his party would continue with Brexit if it won a snap general election in the new year.
The opposition leader told the Guardian he would “go back and negotiate and see what the timetable would be” with Brussels if Theresa May triggered a vote and lost, thrusting his party into power.
Meanwhile, Work and Pensions Secretary Amber Rudd has said European Commission president Jean-Claude Juncker’s behaviour towards women has been “grotesque” after the former Luxembourg prime minister played with a woman’s hair at a European Council meeting.
Mr Corbyn told the paper that he would advocate Brexit if there was a second referendum on the issue, and attacked the bloc over its rules on state aid and competition.
He told the Guardian: “I think the state aid rules do need to be looked at again, because quite clearly, if you want to regenerate an economy, as we would want to do in government, then I don’t want to be told by somebody else that we can’t use state aid in order to be able to develop industry in this country.”
Asked about Labour’s position if there was a fresh popular vote, he told the paper: “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.”
Ms Rudd, who backed Remain in the referendum, launched a scathing attack on Mr Juncker, labelling him “ghastly”.
Mr Juncker and Mrs May were caught on camera having a robust discussion the day after Mr Juncker used a press conference to describe her negotiating strategy as “nebulous”.
Ms Rudd replaced Esther McVey at the Department for Work and Pensions a month ago, having been sacked as Home Secretary over the Windrush scandal.
In a wide-ranging interview, which will fuel speculation she has leadership ambitions, the Hastings MP was asked about Mr Juncker.
She said: “(He’s) ghastly. What I minded before that were those pictures of the way he was holding the Prime Minister. I did not like that.”
Discussing the indecent on his arrival at the European Council meeting, she added: “It’s grotesque. I mean, if that happened in our Parliament, I hope there would be a formal complaint.
“When I used to go the EU for meetings, I often had a terrible cold to insist that I didn’t get enveloped in a bear hug.”