Labour will tonight unveil its celebrity firepower at the east London launch of a charter for the arts. Big guns will include singing stars Lily Allen – who posted a video of herself praising the new manifesto in app-generated tears – MIA and Emeli Sandé, and the film-maker Ken Loach. Labour hopes they will help its promise to invest £1bn in an “arts for all” programme cut through to the electorate. “Every child, whatever their background, should be able to enjoy the fundamentals in life, and access to the arts is crucial to that,” Sandé has said.

Politicians usually have a tricky, not to say distant, relationship with the world of entertainment and the arts, but in an election campaign all this changes as party HQs reach out for VIP endorsements, although MPs may have little idea who these people are. Historically, Labour enjoys stronger support, with notable exceptions such as Michael Caine, Jim Davidson, Julian Fellowes and Gary Barlow.

Recent business research confirms the economic value of high-profile endorsements and political strategists believe the same can apply to policy.

This weekend, the American comedian Rob Delaney, co-star of the sitcom Catastrophe, released a video on Twitter saying he is “crazy” about the NHS and warning the Tories will sell it off to America. In 2016 Mark Ruffalo, Susan Sarandon and Danny DeVito also put their Hollywood might behind Corbyn.

This month, a range of British musicians, from rappers Lowkey and Stormzy to the veteran Brian Eno, have signed up for Labour, alongside comic actors Steve Coogan and Miriam Margolyes. Holding back are Jewish former supporters Maureen Lipman and Tracy-Ann Oberman, both alienated by the party’s handling of antisemitism.

JK Rowling and Eddie Marson have led online criticism of the party leadership.

Green supporters will include John Cleese and Liam Gallagher, who tweeted: “I’m voting for the Green party: the rest of them are all selfish and clueless.”

Liberal Democrat celebrity support is confused by the arrival of the noisy new strategic anti-Brexit drive, with which Hugh Grant is associated.