Alistair McGowan on the set of An Audience with Jimmy Savile
Alistair McGowan on the set of An Audience with Jimmy Savile
© Helen Maybanks

There's a flicker of electricity the moment Alistair McGowan steps out on stage as Jimmy Savile. The turquoise bacofoil shell suit. The lank straggles of white hair. The hand clamped round a hefty cigar. The voice, of course: those flat Yorkshire vowels, that nasal toy car whir. It's all instantly – joltingly – recognisable. This is taboo: a monster brought back to life.

When was the last time you saw Savile as a person – living and breathing, walking and talking? You just don't these days. The BBC has edited all trace of him from Top of the Pops. Jim'll Fix It is out. The man's an image or an audioclip, never anything more. So it's alarming to see him alive and well, in good spirits even. And human. For a second, it has the same danger as a séance.

The notion of McGowan impersonating Savile has been the most controversial thing about journalist Jonathan Maitland's play. It can't be too soon, given that some of the allegations against Savile date back 60 years, but the prospect of mimicry – of a virtuosic performance, of exactitude – seems somehow distasteful. It is, however, the very reason Maitland's play works.

An Audience With… doesn't attempt to get into Savile's head. Most actors talk in those terms when they play real people; they're imagining, not recreating. This doesn't attempt to understand why he did the things he did. It asks how he got away with it; how we failed to see.

Maitland uses a central This Is Your Life style framework to carry biographical information. Host Michael Sterling (Graham Seed) trots us through the facts of Savile's life - £40 million to charity, 20 million viewers ("22 million", coughs Savile) – in the guise of a chummy TV Centre welcome.

Around that are a string of accusations – from journalists, from police, from colleagues, from victims – one in particular, Lucy (Leah Whitacker), an amalgam out to confront the man that abused her aged 12. Knowing the truth of what went on, we get to see how he evades those charges, how, for decades and decades, Savile gave truth the slip and got away with abuse.

Maitland and McGowan give us many answers. In fact, it's the combination that's often quite confounding. McGowan's Savile is openly sexual, even joking around the edges of what's acceptable, and he'll never outright deny an allegation or entirely answer a question. He can be intimidating and litigious, but also quite matey, part of one big happy BBC family that lets him write his own questions. He's also absolutely of the people too, insisting on Jim'll Fix It, rather than Jim Will in full. There's his charity work and his global status, his friends in high places and his Vatican knighthood.

Most of all, and this is where McGowan comes into his own, there's what Savile called "the power of odd". The overall effect of Jimmy Savile – outfit, appearance, mannerisms, language, vocal tics – is almost too much to take in. He is a headspin of a human being: so many bizarre characteristics that he becomes oddly impervious.

McGowan lets you see Savile anew, as a set of traits and tics, not an eccentric or a ogre, and it's that enacted impersonation that justifies Maitland turning journalism into drama. Is there a tendency to read everything he does as covering up for his paedophilia? Yes, and Brendan O'Hea's production is weaker when it strays into fiction, where Lucy's subplot can feel too generic, but this is an illuminating evening nonetheless.

An Audience with Jimmy Savile runs at the Park Theatre until 11 July