It's always strange to watch real people watching their onstage surrogates. The first night at the National of Terry Johnson's Cleo, Camping, Enmanuelle and Dick was riven with the laughter of Barbara Windsor loving every minute of Samantha Spiro playing Barbara Windsor.

In sharp contrast, first time playwright Sarah Helm snuggled up discreetly with her husband, Jonathan Powell, in the stalls at Hampstead Theatre last night as Maxine Peake played a facsimile of herself and Lloyd Owen a rather hunkier version of Powell, who was Tony Blair's chief of staff as Britain went to war with Iraq.

Helm was utterly opposed to the war, and remains so. Powell was only doing his job, and we don't know, from the play at least, whether he's changed his mind.

The theatre was crawling with political commentators looking for clues. At each moment of domestic bickering, for instance, Andrew Pierce of the Daily Mail swivelled his gaze towards the high-flying couple. Elsewhere, David Aaronovitch of The Times and Donald McIntyre of the Independent were checking the dialogue for the accuracy of any new nuggets of information.

All three are fairly keen theatre buffs anyway. McIntyre reminded his guest that he and I had once toured America for six weeks in a student production of Twelfth Night. And I reminded him that his snarling, rebarbative Feste started a trend of dyspeptic Shakespearean clowning that has proved irreversible, even at the RSC.

Helm's light Yorkshire accent was very well caught by Maxine Peake, while Powell's evident lean athleticism -- he climbs mountains and rides bikes -- was certainly conveyed by the basso-voiced Lloyd Owen. The play, which is slightly malformed, is beautifully acted, not least by Patrick Baladi who makes of Tony Blair a figure of almost ghost-like physical uncertainty and petulant self-belief.

This proved that while Michael Sheen might have claimed the Blair franchise as his own, and the former Prime Minister has appeared on the Hampstead stage before, in Alistair Beaton's Feelgood ten years ago, there is still room for manouevre and interpretation.

Beaton generously said as much last night, as he mingled with producers David Aukin and Nick Salmon, as well as the two producers whom Sarah Helm thanks in her programme acknowledgements, Matthew Byam-Shaw and Robert Fox.

An unsually high high-profile headcount also included playwright Howard Brenton, glowing with the success of his Anne Boleyn revival at the Globe (last year's Whatsonstage.com Best New Play Award winner), former Evening Standard editor Veronica Wadley, who told me she now has "the perfect life" without any further elaboration, and Nick Kenyon of the Barbican Centre, who was the guest of Hampstead chair Jenny Abramsky, the former boss of BBC Radio 4.

You could not have invented, in fact, a more perfectly compiled example of a theatrical event by and about the chattering classes exclusively aimed at that same demographic. The play doesn't even have to explain that "Clare" is "Clare Short", one of Tony Blair's most implacable opponents over the Iraq War and definitely not a member of the chattering classes -- her great strength, of course.

Director Ed Hall had his family surrounding him in droves, too; the Hall clan are as loyal and supportive to each other as the Redgraves. Sir Peter really is very bowed and feeble these days, but he waxed lyrical over the prospect of his production of the Henry IV plays opening in Bath next week, even though his rehearsal room contribution stops each day at lunchtime. He was accompanied by Lady Hall, former NT publicist Nicki Frei, as well as his daughter Jennifer -- of whom I once said that she'd inherited her mother's (Leslie Caron) beauty and her father's musculature -- and his daughter-in-law, Ed's wife, Issy van Randwyck, the Scandinavian baroness and chanteuse.
     
The question now is: will the West End sustain a play that, for all its considerable faults and shortcomings, thrives on such an audience, or will everyone who wants to see it, or is involved in its subject matter, get to see it at Hampstead?

Whatever the outcome, there's a self-perpetuating buzz about the play, and now, of course, about Hampstead Theatre itself. Ed Hall has made a huge and instant impact in Swiss Cottage and it will be interesting to see how he maintains the momentum after long recent "guest" seasons from the RSC and his own touring Propeller company.