ROGER ALLAM, thank goodness, is the sort of actor who reads his own reviews. Eventually. "I leave them for about a month and then I read them. I tried not reading them, but it's ridiculous - how can you not read them?"

And how can you not enjoy the experience when you've had the sort of glowing notices that Allam received last year as a leading member of Trevor Nunn's radically new - and, it turns out, hugely successful - ensemble company at the National Theatre. They are reviews that have helped him secure two nominations for much-coveted Olivier awards, which are announced tomorrow.

His Ulysses in Troilus and Cressida was described as "superbly intelligent and witty" by Telegraph critic Charles Spencer. His comic contribution to Edward Bulwer-Lytton's Money (which has won a best supporting actor nomination) was similarly celebrated, with praise mostly occupying the narrow range between "brilliant" and "superb". And he made it three raves in a row when Summerfolk by Maxim Gorky opened to near universal acclaim, with Allam as Bassov, the lawyer (now nominated for best actor).

The Ensemble was conceived as only a year-long venture for 1999, but critical success of productions such as Summerfolk, The Merchant of Venice and Candide has led to either extended runs into 2000 or brief returns. Summerfolk, the last of the Ensemble's six plays, is now back for its second run and will be in rep until May 2.

"It's not been bad, has it?" Allam asks cheerily, when we meet in the concrete bowels of the National Theatre at the South Bank. But while he is clearly enjoying the moment, there is also a barely concealed frustration. At 45, he knows that no amount of good notices will help shake off the well-earned but at times unwanted epithet, "an actor's actor".

He pulls a face when I use the phrase, well aware of what it signifies: an actor whose talent and technique keeps him in work in the theatre but one who is rarely seen on the television screen or in the cinema. "What to do about it, I don't know," he moans, his features briefly looking as crumpled as the cream linen suit he is wearing for the part of Bassov. "I'd love to do more television and some film stuff if it came along. It would be very useful, both in terms of money - thank you very much - and also the fame. It moves you higher up people's lists."

Allam is both encouraged and good-humouredly frustrated by the fact that others held in similar high standing by their peers have made the big commercial breakthrough. The not altogether dissimilar Alan Rickman, for instance, hit the big time after going to Broadway with the original Royal Shakespeare Company production of Les Liaisons Dangereuses, while Ken Stott - an actor's actor for so many years - took the bold decision not to accept any work until someone offered him a decent television part or a film.

"Yes, it all suddenly happened for Ken, didn't it?" muses Allam. "I know the theory is that you're supposed to stay out of work until something comes up. But my problem is if I hang around I run out of money and get bored - and I tend to get more interesting offers in theatre than I do in television."

The most recent interesting offer, of course, came from Nunn asking him to join the Ensemble, though Allam initially turned it down. "Then the other things moved a bit - and Trevor Nunn was very insisting and flattering." Among these "other things" was The Creatives, a sitcom set in an Edinburgh advertising agency now enjoying a second series on BBC2.

What persuaded him to return to the theatre, however, was the quality of parts that Nunn had to offer. "With Ulysses, the appeal was a mix between those two big arias that give you a lot of opportunity and a simple, childish delight in running about with swords. Then there was Money, where I was a slightly eccentric, rather Dickensian character. And now there's Summerfolk, where it's nice to be wandering around in relatively ordinary clothes, just talking."

Just talking is something he does well, possessing a deep and beautifully modulated voice that belies his East End origins ("my father was a vicar in Bromley-by-Bow"), but does great credit to the singing teachers whose encouragement left him seriously considering a classical singing career right up to the moment he left Manchester University with a degree in drama. "Although I didn't pursue the singing, the voice was always there - vast amounts of red wine and cigarettes did the rest."

It was the National Theatre - then at the Old Vic - that first drew him to the theatre. Knowing that he was studying Hamlet at school, a family friend suggested he go and see Tom Stoppard's Rosencrantz and Guildenstern Are Dead. "Being on my own in this big crowd of strangers in the Old Vic and seeing this great play; that was it really. I knew I wanted to be part of that."

And now he is part of the Ensemble. "I spent most of the 1980s at the RSC, so I've done a lot of work like this. It has been very good here," he says.

The experience was made all the more pleasant last year by having his girlfriend, the actress Rebecca Saire, appearing in another National Theatre (but non-Ensemble) production, Private Lives. "First time that's happened; it was very nice," he says.

As our conversation draws to a close, his thoughts return to Summerfolk. "It's about the sort of people we don't meet at the end of The Cherry Orchard, the people who would have lived in the summer residences that the cherry orchard is cut down for, the new middle class: doctors, engineers, lawyers.

"With hindsight, it was a class at a crossroads, unsure whether they were going to go down the road of individual well-being or the old revolution route." Almost a century after it was written, he believes that Gorky's work will have a resonance - "Although clearly our choices aren't quite so stark." And with that he is gone. Roger Allam is wanted on stage. Again.