SENIOR Labour figures warned there must be “no turning back” on the party’s transformation under Jeremy Corbyn as polls closed last night.

Huge disparities between opinion polls in the final 24 hours had prompted a feeling among activists of all parties that voter turnout and the election day ground game would be more important than ever.

Several Labour MPs continued to criticise and distance themselves from Mr Corbyn during the campaign.

Sedgefield candidate Phil Wilson and Enfield North candidate Joan Ryan used their election addresses to snipe at the Labour leader — while Barrow and Furness candidate John Woodcock said he “will not countenance ever voting to make Jeremy Corbyn Britain’s prime minister.”

But prominent parliamentary backers and union leaders have warned that the party’s leftward shift cannot be undone.

Labour shadow Cabinet Office minister Jon Trickett told the Star: “These have been electrifying moments in the most remarkable election of my lifetime.

“Jeremy Corbyn, his message and the Labour manifesto have offered a sharp contrast to the dead hand of Mrs May.

“Millions of people across Britain have responded to our campaign and revitalised our politics. We must not lose the dynamic and energy unleashed in the last few weeks.”

With Labour’s manifesto incorporating more trade union policies than in a generation — including beefed-up workers’ rights, the repeal of anti-union laws and mass investment in industry — reps were pounding the streets last night in the hope of a Corbyn victory.

Bakers, Food and Allied Workers Union leader Ronnie Draper said: “There’s definitely no turning back. What Corbyn has done has changed Labour, and changed it for good.

“Even if Theresa May gets in, she’s going to fall on her arse. We know the stuff she’s saying is going to be lies.

“Whereas Labour’s manifesto is not just as a gimmick — it’s a real lust for change in the country and the party.”

Labour’s campaign was also boosted by a surge in support among young voters, and new mobilising tools developed by left faction Momentum, such as a website to direct activists to their nearest marginal constituency.

Momentum chairman Jon Lansman said: “The mood among younger voters is enormously encouraging in the long term — the future is with us.

“Politics is shifting. The manifesto won outstanding popular support way beyond the left. Our members have shown their value in the way they’ve been mobilised in this election.

“Over the past two years Labour has built a movement to transform Britain, and it is vital that is maintained as we move forward.”