Labour supporters of a second Brexit referendum have failed to force Jeremy Corbyn to commit to a public vote in all circumstances, after a marathon five-hour meeting.

The party’s ruling national executive committee agreed a manifesto for the European elections “fully in line with Labour’s existing policy”, a source said.

It means Labour is only pledged to support a fresh referendum if it cannot secure “the necessary changes to the government’s deal or a general election”.

The decision – widely criticised as a fudge – represents a victory for Mr Corbyn over shadow cabinet heavyweights including Tom Watson, his outspoken deputy leader.

The Labour leader is determined to avoid alienating his Leave voters by sticking to a policy of a referendum to prevent what he dubs a “Tory Brexit”, or a no-deal Brexit.

Put It To The People march: Best of The Independent’s pictures Show all 24 1 /24 Put It To The People march: Best of The Independent’s pictures Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent Put It To The People march: Best of The Independent’s pictures Put It To The People protest 23 March 2019 Angela Christofilou/The Independent Angela Christofilou/The Independent

It leaves open the possibility, however slim, of Labour helping to force through EU withdrawal if the Conservatives concede a customs union and to his demands on the single market, plus worker and environmental rights.

However, in reality, that attempt looks doomed – after Theresa May set a deadline of just one week to agree a compromise, or she will abandon the cross-party talks.

For that reason, some pro-EU Labour MPs stopped short of criticism. Ian Murray, a former shadow Scottish secretary, said backing for a Final Say referendum had been “upheld at last”.

“Given there won’t be a general election and the Tories will not agree customs union and single market, the @UKLabour EU manifesto commits to a public vote,” he tweeted.

Ben Bradshaw, a leading pro-referendum Labour MP, echoed the message, tweeting: “There won’t be an election cos Tory MPs won’t vote for one. #peoplesvote only thing left. Bingo!”

Labour’s pro-EU wing was also pleased that the party would now have to rapidly rewrite the controversial European election leaflet which made no mention of a fresh referendum.

Mr Corbyn’s office had been confident of resisting a shift to supporting a further referendum in all circumstances, enjoying the support of at least 22 of the 39 members of the NEC.

He could rely on the backing of the giant Unite union, despite other big unions – including the GMB, Unison and Usdaw – swinging behind another public vote.

But more than 20 Labour MEP candidates had defied their leadership by pledging to back a referendum and then campaign to remain in the EU.

And a letter from MPs and MEPs calling for a public vote on any Brexit deal has reached 118 signatories, meaning the majority of non-shadow cabinet MPs back it.

Earlier, Tom Watson, Labour’s deputy leader, walked out of a shadow cabinet meeting after Mr Corbyn refused to allow its members to see the draft referendum policy, ahead of the NEC gathering.