Labour leader Jeremy Corbyn is happy to "accept Brexit at any cost", according to the man hoping to dethrone him. Owen Smith issued the attack after a spokesman for Corbyn reportedly repeatedly "refused" to tell lobby journalists that the left-winger wants the UK to remain a member of the free trade area.

"Tens of thousands of Labour members and trade unionists will be worried to hear that Jeremy Corbyn appears to agree with David Davis that our membership of the single market is not worth fighting for," Smith said.

"I have been consistent in saying that trade with Europe is in our national economic interest. It brings jobs, growth and investment.

"Jeremy seems happy to accept Brexit at any cost – even if that means putting British jobs and investment at risk."

Smith, who has called for a second referendum to "ratify" Brexit, made the comments after Corbyn failed to grill Thersea May over the issue at this week's Prime Minister's Questions (PMQs).

The Conservative government was left red faced after the Brexit Secretary David Davis suggested it was "improbable" that the UK would remain in the single market because of May's desire for tougher immigration rules.

But a Downing Street spokeswoman later distanced Number 10 from Davis' remarks, claiming he was voicing a personal position at the despatch box. Corbyn, a long-time Eurosceptic, drew criticism from his own party after the EU referendum for his performance for Remain during the campaign.

The Labour leader faced a string of resignations from his shadow cabinet and 172 Labour MPs backed a motion of "no confidence" against him.

If Corbyn fails to back the single market opinion, he will also be put at odds with Mayor of London Sadiq Khan and many of his own MPs.

May, meanwhile, told MPs today she the government will not give a "running commentary" on their Brexit negotiations with Brussels.

The Conservative premier will also not trigger Article 50 of the Lisbon Treaty, the official mechanism to split from the EU, this year.