"Frost/Nixon" (The Guardian Review)

As well as creeping impatience, there is a weird sense of deja vu watching the talky, inert drama which opens tonight's London film festival - about David Frost's legendary TV interviews in 1977 with the disgraced ex-president Richard Nixon. Its screenwriter, Peter Morgan, gave us The Queen, starring Michael Sheen as Tony Blair and Helen Mirren as the monarch.

Now, once again, Sheen plays a media-savvy and weirdly depthless figure facing off against a shrewd, but wounded head of state. For comparison, that earlier piece could be retitled Blair/Liz. Ron Howard directs Morgan's own adaptation of his hit stage play, and the embattled former chief is played by Frank Langella, 30 years on from his performance as Count Dracula.

Michael Sheen is Frost: smooth, plausible, consensual, blessed with the fleet-footed nimbleness that comes with being unencumbered by gravitas. Nixon is glowering, serious and suspicious, but with a wily charm and the easy, slow-moving gait of a man accustomed to the exercise of real power.

This was a duel of wits and a struggle for survival. Landing a punch on Tricky Dicky would resurrect Frost's crumbling TV career; avoiding the punch might retrieve Nixon's historical reputation.

Like a riverboat gambler, Nixon figured on playing Frost for a mug.

They had agreed on three soft interviews on uncontroversial topics before the tough, final one on Watergate - with a strict two-hour time limit on each. The old crocodile reckoned he could overawe and bamboozle Frost, wriggling out of the tough questions while time ran out, so all that would be left on the record would be sycophancy.

Sheen's impersonation of Frost starts with the classic tics: the head waggle, the nasal droning, the tiny soupçon of Brucie - but he soon sounds like ... well ... Tony Blair.

When Sheen's Frost initially watches Nixon's resignation on TV, he has the same glassy-eyed expression - part stunned, part calculating - that Sheen's Blair had on watching the mourners with flowers outside Kensington Palace. But there's a scene where he's selling the idea of a Nixon interview to a sceptical John Birt (Matthew Macfayden) in the LWT canteen, where Frost starts to look and sound like Alan Partridge. Knowing you, Impeached Villain, knowing me, Underdog Lightweight, A-ha?

Frank Langella rolls over Sheen like a tank in a way that Nixon failed to do with Frost in art or in life. Frost is nervy, darting, ineffectual, but Nixon moves slowly and easily, as if to the beats of some invisible band playing a leisured version of Hail to the Chief. Nixon is a juicy part and Langella extracts every tasty drop.

But the performance has no room to grow. Frost and Nixon have no "real-world" encounters: it is like a boxing movie about two combatants who never meet outside the ring. Of course, they confront each other before and after the main event, with some mind games from Nixon, but these affairs are as formalised as the interviews themselves.

It's an intriguing subject, and it usefully reminds us of David Frost's real entrepreneurial courage in creating this TV moment: gambling hundreds of thousands of dollars from his own pocket before any sponsorship or network sales were guaranteed.

But transferring this small-screen drama to the stage was a more interesting medium-shift than moving it to the big screen.

Eventually, the most interesting thing about the movie is a mirage: the optical illusion of a prickly Tony Sheen-Blair demanding but failing to get answers from a disgraced US president about the invasion of Cambodia, a corrupt foreign policy, the wholesale slaughter of civilians. A lot of hot air - but not much real heat.

• Peter Bradshaw is the Guardian's film critic