First Night: The King's Speech, Yvonne Arnaud Theatre, Guildford

Much more than a chance to turn a royal hit film into royalties

It has raked in more than $400m worldwide.

It has garnered four Oscars and seven Baftas and ranks as the most successful British independent movie of all time. Now The King's Speech – the movie about George VI's struggle to overcome his stammer – takes to the boards in a stage version by David Seidler, the author of the screenplay.

Everybody has seen the film and the performances of Colin Firth, Geoffrey Rush and Helena Bonham Carter are still fresh in the collective mind. So what is the point – apart from the attempt to make these royals even more synonymous with huge royalties – of re-presenting the material in a different medium?

The author has let it be known that the stage treatment was completed before the screenplay as a way of concentrating his mind on the essentials of the story. And a moving clarity of focus proves to be one of the distinct merits of this theatrical version, premiered now in Adrian Noble's incisive, uncluttered production.

The piece is played on a circular revolve divided by a huge, black-framed translucent screen. The effect can be that of a mirror. This means that there are moments here when Charles Edwards's excellent Bertie appears to be a kind of reverse-image double of Lionel Logue, the Australian speech therapist whose undeferential unconventionality is given a playful bite by Jonathan Hyde. Both of these men are failed actors who have disappointed their fathers – with our sense of Lionel's thwarted ambitions to be a professional thesp heightened by the humiliating auditions for Shakespeare roles he undertakes under the glare of a spotlight.

In the theatre, it becomes all the clearer, too, that the story is like an inverted version of Pygmalion, but where Eliza Doolittle needed to be smartened up, the inhibited Bertie needs loosening up and this requires digging into his traumatised childhood.

Charles Edwards is, ironically, one of the most fluent and witty of verse speakers in the business. Where Colin Firth's Bertie looks exhausted, Edwards, in a touching and often very funny portrayal, suggests a quicker and more highly-strung spirit flailing in the intolerable net of his speech difficulties.

Details that got left out of the film are reinstated. Emma Fielding is an amusingly tart stickler for protocol as Queen Elizabeth. The horribleness whereby Bertie's brother Edward VIII (Daniel Betts) tried to dish his brother by landing him with speeches he could not manage, while eventually saddling him with a crown he dreaded, comes through with a sickening force. I arrived thinking that this was a redundant exercise and leave with the thought that good material responds well to different approaches.