I remember Watergate as if it were yesterday; reading the reporting of Simon Winchester and Jonathan Steele in The Guardian through 1973-74 as every single day a new circumstance would dribble out, and the vice round the neck of the conspirators tightened inexorably. Peter Morgan in 2006 plugged a little gap in the Watergate market with his Frost/Nixon, recounting the setting-up in 1977 of a series of syndicated 90-min interviews between the disgraced ex-President and Frost, the once-tough satirist, now dwindled into a world of powder-puff questions on the chat show circuit.

The anodyne room set, doing duty as a hotel room and TV studio, is enlivened by the presence of a hand-held videotape camera on the floor and a TV monitor. I wondered if directors Gregor Roach and Alex Marks might have arranged the camera to be shoved a bit more in the faces of interviewer and interviewee, while the TV monitor at an acute angle was all but invisible to the audience near me. Had it been central and larger, or ideally had there been blown-up projection on the back wall, the sense of battle lines being drawn up by the two parties might have been even more pronounced.

Morgan's structure of his material has narrator and noted Nixon-phobic journalist Reston commenting acerbically on the action, which switches between the jockeying for position beforehand, the interviews themselves and, briefly, the aftermath. In fact, half of the running time has hurried past by the time the first interview rolls out. I might possibly have preferred more interview and less set-up, but no doubt the playwright was wary of his material becoming too static.

All the acting was competent and in many cases better than that. Martha West's narrator was occasionally hesitant in speech, perhaps from first night nervousness, but there's the makings of a very good performance in there and for sure she'll demonstrate that as the run goes on. Charlie Wade's smiling Frost ('He'll be a big, wet kiss' is the assessment by Nixon's aide) makes of him a rather attractive figure; possibly too attractive, since I didn't quite glimpse the cynicism and thrusting ambition lurking just below the surface. But Charlie conveyed considerable emotion towards the end as he came under pressure from his backers and then made genuine connection with his interviewee.

But the company's trump card - and the man himself is briefly seen in a clip at the end to remind us that the nightmare goes on – is its Nixon. Morgan cunningly holds him back, but when he finally appears, in suit and miniature stars-and-stripes lapel badge, Gavin Fleming's impact is electric. He told me afterwards he's studied the man and his mannerisms. And it shows - but this is no caricature. Everything is subtle; controlled movement, body language – he embodies the practised politician with oily laugh ('the candidate for office these days needs a full head of hair, not have to shave twice a day and not perspire'), the prehensile bearing as he assumes sincerity whether appealing to the religious right or the swallowers of his schmaltz. The smooth voice was a couple of times transfigured into such frustrated rage that you felt you were looking deep down into the old rogue. And as the clinching admission of culpability: 'I was involved in a cover-up' came out between gritted teeth, you could have heard a pin drop. This is one of those rare student acting performances to be treasured.

Well-directed and thoughtful, there's food for thought here in egregious misuse of power and stoking of mistrust in the political class. Strongly recommended.