Stars John Hawkes, Helen Hunt, William H. Macy, Adam Arkin; directed by Ben Lewin; 95 minutes.

Recently Intouchables, about a quadriplegic man and his carer, made a splash. I wasn't as enthusiastic about it as some, finding it well-acted and appealing but a bit too broad and contrived. The Sessions, also based on a true story, also focuses on a severely disabled man who forms an unusual relationship, but its lower-key approach worked better for me. It's poignant, sometimes funny, and sometimes raw.

Mark O'Brien (John Hawkes) has been living for most of his life in an iron lung since being incapacitated by polio as a child. He can speak and uses a pointer to type (he's a poet and a journalist). Although he has carers, his life is somewhat lonely, and at the age of 36, after being asked to write an article on sex and the disabled, his own feelings are stirred. He decides to seek out his first sexual experience. Eventually, he gets in touch with Cheryl (Helen Hunt), a professional sex surrogate. She is very clear on the difference between her work and that of a prostitute: she does not encourage repeat business and it is not necessary to pay her up front. And she wants to keep the focus firmly on him, not wanting to talk about her husband or her teenage son.

As you might expect, a lot of the time is devoted to ''the sessions'' - the encounters, strictly numbered, in which Mark and Cheryl make physical contact - and, unexpectedly for her, bond on an emotional level, too. While there's more of her body on show than his, it doesn't feel gratuitous or sexist, for a change, and the sexual encounters are handled tastefully. This isn't a pornographic movie but a depiction of an unusual relationship that shows how hard it can be to separate sex from emotion, and the complications that ensue.

The emphasis here is on the performances and they are excellent. Hunt is excellent as the woman who finds it hard to maintain professional distance and Hawkes is utterly believable and moving as a man with a sharp mind in a frail body.

There's good support, too, particularly from the always reliable William H. Macy as Mark's priest, a shaggy-haired, wryly humorous man willing to consider going beyond the Church's customary attitude to sex outside marriage in this particular case.

Writer-director Ben Lewin worked a lot in Australian and American television and handles this poignant material with skill: there's a real feeling conveyed with regards to Mark's frustrations, longings and limitations. If it's occasionally a little lacking in detail - there's not much about how Cheryl's husband and son have dealt with her unusual occupation - and sometimes a little predictable in its turns, it's still very effective. The melancholy score underlines the bittersweet tone of the movie, which - despite its subject matter - manages to be both funny and moving.