Jeremy Corbyn is facing a growing backlash from his colleagues after he explicitly said Labour in government would not seek to retain membership of the single market after Brexit.

Contradicting the Labour leader, Carwyn Jones, the Welsh First Minister, however, claimed there is no need to leave the single market on leaving the European Union and that access could be maintained through a Norway-style model.

Mr Jones told BBC Radio 4’s Today programme: “If we’re not in the single market, we would be having a debate about how to access it, not how to leave it.

“There is no need to leave the single market, even as we leave the EU,” he added, in comments that were echoed by Labour MPs on social media, once again highlighting the torturous position the party is in over Brexit.

The comments came after Mr Corbyn told BBC’s Andrew Marr Show that Britain would have to leave membership of the single market because it was “inextricably linked” to membership of the bloc. While the party’s manifesto for the general election pledged to focus on “retaining the benefits” of the single market and customs union, it was not explicit on whether Britain would actually remain inside the institutions.

Mr Jones’s intervention also led to pressure being applied by the SNP on the Scottish Labour Party to clarify its position on the single market. But a Scottish Labour spokesperson told The Independent: “Kezia Dugdale and Jeremy Corbyn have always been clear that Labour supports a jobs-first Brexit.

Labour would take Britain out of the EU single market, Corbyn says

“As Kez has repeatedly said, we support tariff-free access to the single market for the UK. Jobs, the economy and retaining benefits of the single market and the customs union are our priority.”

Wes Streeting, a Labour MP and leading support of Open Britain, the campaign group against a hard Brexit, also criticised the party leader, adding: “The idea that membership of the single market means membership of the EU is factually untrue – look at Norway and Iceland for start.

“Labour needs to fight for a Brexit deal that puts jobs first, protects our economy, and retains rights for workers. Leaving the single market would undermine all those objectives. Leaving the biggest and freest trading bloc in the world will cost jobs, and the loss of protections enshrined in EU law could make it easier for a Tory Government to cut workers’ rights.

“Staying in the single market while leaving the EU is perfectly possible, and would be the best Brexit deal for working people and Labour communities.”

The senior Labour MP Chuka Umunna continued: “Taking single market and customs union membership off the table in the Brexit talks is the Tory position, it should not be Labour’s.“

Stephen Doughty, the Labour MP for Cardiff, welcomed Mr Jones’s comments, posting on Twitter it was “good to hear” the Welsh First Minister “speaking up about [the] importance of the single market + customs union”.

But the divisions in the top of the party’s ranks over another EU institution – the customs union – were also highlighted as Barry Gardiner, the Shadow International Trade Secretary, told BBC Radio 4’s Westminster Hour that remaining in the customs union would be a “disaster”.

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His intervention came despite the Labour leader just hours earlier, on the BBC’s Andrew Marr Show, claiming the party had yet to make a call on the customs union.

Mr Gardiner, who also dismissed the idea of remaining in the single-market in a similar fashion to Norway, added: “I just want to point out the issues around the customs union, we leave the customs union because only member states of the European Union are members of the customs union.

“Other countries like Turkey have a separate customs union agreement, but the trouble with that is that it gives you an asymmetrical relationship with the third party countries that the EU does a deal with.

“So the EU could do a deal with another country – let's say America – which we would be bound by in the UK, we would have to accept the liberalisation of our markets, we would have to accept their goods coming into our markets on the terms agreed by Europe which could be prejudicial to us but we would not have the same access into America's markets, we would be bound to try and negotiate it. But why would America give us that access when it's got all the liberalisation of our market that it wants?

“It's a disaster.”

The disarray at the top of the party’s ranks came as a new Ipsos-Mori poll for the London Evening Standard found that 49 per cent of British voters wanted to prioritise access to the single market in the Brexit negotiations, rather than immigration.