Theresa May has agreed to hold fresh talks with Jeremy Corbyn's over his plans for a soft Brexit that would keep Britain tied to the Single Market after Brexit and locked in a customs union with the EU.

In a letter to the Labour leader, the Prime Minister did not rule out Mr Corbyn's demand for a "permanent" customs union although she said it would present a "negotiating challenge".

She also agreed to talks on Mr Corbyn's call for "close alignment" with the Single Market, as well as committing to asking Parliament if it wishes to follow EU rules on workers' rights and environment standards​.​

The letter alarmed Tory Eurosceptics, who fear the Prime Minister ​could ultimately change tack and back keeping Britain in a Customs Union with the EU.

Jacob Rees-Mogg, a senior Eurosceptic Tory MP, said: "As the 2017 Conservative manifesto promised to leave the Customs Union it would be more consistent for the Prime Minister simply to rule one out."​