Labour has opened the door to reversing Britain’s decision to leave the European Union, by backing a potential second referendum.

The party’s conference in Liverpool voted overwhelmingly to keep the option of a fresh vote “on the table”, after shadow Brexit secretary Sir Keir Starmer explicitly stated that it could include the option of staying in the EU.

Sir Keir won a standing ovation from a large majority of delegates, though some remained firmly in their seats.

His declaration that “nobody is ruling out Remain as an option” was not included in printed copies of his speech distributed to the media, sparking speculation that he may have gone beyond the position agreed by Labour’s high command.

But leader Jeremy Corbyn said that the contents of the speech had been cleared by his office in advance.

He said Labour would subject any deal reached by Theresa May with Brussels to the six tests set out by Sir Keir, including that it should deliver “the exact same benefits” as single market and customs union membership.

And he said Labour was prepared to vote the PM’s deal down.

Both Sir Keir and shadow foreign secretary Emily Thornberry told the conference that they would personally vote Remain in any re-run referendum.

But Mr Corbyn himself repeatedly declined to say which way he would vote, telling Five News: “It depends what the question is in the referendum… We will decide as a party when the referendum comes what our position will be.

“I think it’s pretty obvious what party members are thinking at this conference.”