Mandelson: The Real PM?

The filmmaker Hannah Rothschild spent several months earlier this year, in the run-up to the May election, following Peter Mandelson, the former Business Secretary, at close quarters as he enjoyed the last hurrah of his surprise return to government. The man they called the 'Prince of Darkness' after engineering Labour's mid-'90s rebranding returned to Westminster from Europe in October 2008 to take charge, as the film tells it, of a £21 billion departmental budget and to sit on 35 out of 43 Cabinet committees. He also had a reputation to rebuild after being unceremoniously ditched from Tony Blair's inner circle when he was forced to resign from government for a second time in January 2001 over the Hinduja passport affair.

Rothschild films Mandelson at home, at work, in his dressing gown and, brace yourself, in his white briefs while he changes for dinner in his ministerial office – an office which is a glum annex to an equally glum open-plan department, where he breezes easily between shoots for 'Tatler' and meetings with his aides about the party manifesto. Yet there's nothing glum about the Mandelson we meet: he's lucid, energetic and happy. There are just two scenes for which he relaxes the Machievellian Tigger act just a bit. At home, reclining on a low chair, clearly tired, he gushes in a low voice, in low light, about Tony Blair – 'I love him so much… genuinely nice person… very effective Prime Minister… genuinely New Labour' – but then checks himself as he turns soppy and decides that's enough, the interview is finished.

The other wobbly moment comes after the election, when Rothschild comments that her interviewee's usual 'sparkle' is absent. Mandelson snaps that he's 'perfectly happy to answer questions'. But she's right: he's downbeat and unusually reticent. The election has briefly knocked him sideways, even if, as you imagine, he always knew Labour would lose it.

Rothschild rides with Mandelson in his ministerial car and shares tables with him on trains. She interviews him at home and is with him when he's talking to Gordon Brown on his mobile, reassuring the Prime Minister that his peformance in the first leaders' debate was tip-top. He comes across as you imagine he would like to: as the power behind the throne. He's the co-author of this film, surely, in all but name? He proves to be brilliantly adept at controlling his image. Why else would he let a camera into his life? It's not a criticism of the film; it simply lends it another layer of interest.

The reactions of Alastair Campbell and George Osborne to the presence of Rothschild's camera at the third leaders' debate speak volumes about the whole enterprise. 'Oh for God's sake… "The Peter Mandelson Show"?' sneers an amused, knowing Campbell, while Osborne teases Mandelson before they go live on television together: 'When are we going to see your film, Peter? June? July?' Mandelson, as ever, has an answer: 'I might extend it, add some scenes in Corfu, perhaps.' Osborne laughs. Mandelson, of course, is referring to the time in summer 2008 when he is said to have 'dripped pure poison' into Osborne's ears about Brown while both were holidaying on Corfu and enjoying the hospitality of Nat Rothschild, the financier and the filmmaker's younger brother.

We must accept, then, that Rothschild is in an interesting position: she has Mandelson's trust and he, in turn, has given her unprecedented access. But let's not imagine Mandelson has removed his political mask for a friendly, filmmaking acquaintance. He doesn't once say a bad word about Brown, while, shrewdly, he has since let the same mask slip a little to help sales of his book - and, one assumes, to distance himself from Brown when it is more politically expedient to do so. Here, he describes Brown as a 'cross between a snow plough and a combine harvester' and criticises him only for not being able to do his tie up properly.  Rothschild protests at one point when he is vigorously defending Brown from accusations of bullying. 'But I've heard him on the phone to you getting cross,' she says. The response is typical Mandelson: 'He's just saying to me: hear my pain.' His comic timing is second to none.

The fun of the film – and it's an intensely fun film to watch - emerges from being able to watch Mandelson at work. He adores indulging himself with a vast retinue of staff. He wants to appear powerful and doesn't mind appearing vain. Vanity and the trappings of power are his right, he believes. Is he performing? Most certainly. But one imagines he's always performing. Life is work for him, and work is a performance. 'By and large, I'm working,' he says. 'If I'm not working, I'm sleeping.' He does, however, slip off home one Friday night during the election to relax by watching Tom Ford's 'A Single Man' on DVD. At one point, Rothschild asks whether he would prefer to be known as a 'Mummy's boy', like David Cameron, or the 'Prince of Darkness'. 'Oh, God, "Prince of Darkness", without a doubt.' He can rest easy. His reputation is in tact. Yet there's a lot of light and laughter about him too, and it makes him an endearing and sly character with which to spend an hour or so.