An Audience with Jimmy Savile, Park Theatre, review: Insightful rather than insensitive, Alistair McGowan captures the monster behind the man

Alistair McGowan is brilliant as the intimidating thug who plays the clown

Alistair McGowan plays the paedophile DJ Jimmy Savile

Cashing in on misery? Insensitive to the victims? Too soon after the traumatic revelations? In advance of its premiere Jonathan Maitland's play has been accused of all these things. But it emerges as a responsibly shocking, well-researched, and patently honourable piece.

The poet Shelley said that it was the job of art to help us to imagine what we know. In its best sections, that's what this play does with the Jimmy Savile scandal and the question of how he managed to forge a unique role for himself in English culture – charity fund-raiser extraordinaire; court jester to royalty, Prime Ministers, Roman Catholic Archbishops – and to exploit this in order to cover up his simultaneous career as a prolific paedophile.

The proceedings shuttle between two scenarios, setting up a blackly ironic counterpoint that's emphasised to just the right degree in Brendan O'Hea's mordant production. In one, the newly-knighted Savile is soaking up the adulation on a This Is Your Life-style programme; in the other, Lucy (Leah Whitaker) a 30-year-old woman raped by him in hospital when she was 12 (a composite of several of his victims) is battling to convince her father, lawyers and the police that this “national treasure” should be brought to justice. Jim fixed it for one tearfully grateful guest on the inset tribute programme to swim with dolphins when she was a child. That character's memory of a dream come true contrasts bleakly with the lifelong nightmare he inflicted on girls such as Lucy.

Jimmy Savile (left) and Alistair McGowan who is playing him at the Park Theatre (Getty Images/ Helen Maybanks)

It was a smart move to cast the excellent Alistair McGowan as Savile since it arouses expectations of a likeable comic impression and so heightens the chilling glimpses we get of the intimidating thug under the clown persona that so calculatedly harnessed “the power of odd”. The play is able to flesh out the transcript of police interviews. And it imagines that he's caught molesting a young woman in the advert break of the programme (this is reported not shown). In all cases, he is able to scare off challengers by one or more of these tactics. There's the breath-taking misogyny with which he discredits victims precisely targeted because they are vulnerable and unlikely to get a fair hearing (“Posh borstal for disturbed girls, bad' uns” is how he describes Duncroft School). There's the threat of reducing you to rubble by the libel laws and high-placed friends. And there's the insinuation that it wouldn't look at all well if you were seen to be the party-pooper on his great charity work.

The menacing assertiveness and the name-dropping megalomania in McGowan's portrayal make is easier to understand how Savile got away with it. “We are family at the BBC. We look after one another. That's why we are the best in the world,” he coercively tells the This Is Your Life presenter (Graham Seed) as the advert break incident is swept under the carpet.

The idea recurs that this principle of family loyalty and closing-of-ranks accounts for how he duped other institutions, such as the NHS. The play ends in a sense of release, though, as Lucy finally confronts Savile. “Rape, marathon; rape, marathon”; does this Roman Catholic really believe, she asks, that the one atones for the other and that his ledger is in the black? “If you do good just to do bad, you're not doing good at all”. She gets furious denial and a punch in the face for her pains. But the encounter liberates her and, even if wishful rather than factual (I don't know), feels like legitimate conclusion to this scrupulously assembled, dramatically potent posthumous trial.

To 11 July; 020 7870 6876