Barry Gardiner in the tall grass over Labour's Brexit splits

Labour's shadow international trade secretary claimed he was trying to 'advance thinking' on Brexit among Jeremy Corbyn's top team during a difficult interview that saw him challenged over his description of Labour policy on leaving the EU as 'bollocks'.

Emma Barnett talking to Shadow International Trade Secretary, Barry Gardiner, on the BBC1 current affairs programme,The Andrew Marr Show at the weekend. Picture: PA

Critics claimed Barry Gardiner’s appearance on the BBC’s Andrew Marr Show was a “car crash” after he failed to stand by his comments, and refused to acknowledge that Labour’s candidate in an upcoming by-election had already broken with party policy on Brexit.

Janet Daby, a moderate who was selected over the weekend to contest the safe seat of Lewisham in London, has said she is “pro-EU” and wants the UK to “stay in the single market and customs union”.

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Challenged by guest host Emma Barnett, Mr Gardiner insisted: “She supports the Labour party position.”

Mr Gardiner was also played a recording of an appearance at a think tank in Brussels, where he said Labour’s demand that the government secure the exact same benefits of the single market and customs union as part of its Brexit deal “always has been bollocks”.

Mr Gardiner said: “Sometimes you have conversations in private, and the reason they are held in private is because you can advance thinking and you can actually then try and, if all you ever do is stick by the given line, you’d never actually advance it because you’d never discuss anything with people – that’s the reason for holding things in private.”

Brexit minister Steve Baker said: “Gardiner has repeatedly failed to support Labour’s position on Brexit. If Labour’s own top team think Jeremy Corbyn’s Brexit policy is rubbish, what confidence are the public meant to have in him?”

The Labour front-bencher was also criticised for claiming there was no way for the UK to stay in the single market after Brexit. Labour MP Chris Leslie, who backs the People’s Vote campaign for a referendum on the terms of the UK’s Brexit deal, said Mr Gardiner was “clearly confused”.

“European Economic Area membership would maintain our single market participation,” Mr Leslie said. “That was why all Labour MPs were whipped to vote on 13 December by the front bench for an amendment saying, ‘No Minister may, under this Act, notify the withdrawal of the United Kingdom from the EEA Agreement’.”

The Unite union boss Len McCluskey repeated the claim that Brexit meant leaving the single market on ITV’s Peston on Sunday, prompting fellow programme guest Nicola Sturgeon to tweet: “It’s simply not true.”