The Caretaker, Trafalgar Studios, London

Must be worth a bob or two, this," says Jonathan Pryce's Davies, surveying the flotsam a shipwrecked life has washed up in a room in Shepherd's Bush. But not three, one thinks of the mounds of furniture, crates, and crockery, all the brown of lavatory and tobacco stains. The tramp says he left his wife when he came across a saucepan with her dirty underwear in it. Now he's living in one.

As Christopher Morahan's near-flawless production shows, there is gold to be mined from the detritus of these men's lives and their worn scraps of dialogue. The tramp's gratitude when Aston (Peter McDonald) offers him the shelter of his squalid, impersonal room soon turns to resentment when Aston ignores him. He pleadingly, then roughly asserts his humanity to Aston and to his brother, Mick (Sam Spruell), the thug who owns the house. Aston and Mick, on stage together only once, pass in silence.

Davies can be and has been played as a monster from the depths or a voice in the wilderness, but Pryce's tramp is precisely, painfully real. His scraggy beard, his back hunched in defensiveness or pretended sagacity, his grumbling and his whine are those of a homeless man whose desperate sycophancy swivels from brother to brother. Pryce's helplessness and bewilderment – he is the only character who behaves normally – make him our surrogate, but we can see, as he does not, that he is being used by the brothers, who cannot communicate directly and will be discarded when they do.

When Davies and Mick are the contenders, the tramp has our pity. Though Spruell brings the needed excitement to the play, he swaggers a bit too much. His cat-and-mouse teasing could be silkier and more offhand. But with Aston's long speech about being sectioned and forced to have electroshock therapy, our allegiance shifts. Like Pryce, McDonald never stoops to ingratiation. Instead this wonderful actor holds Aston's heart as if it were a small, frightened bird, then lets it go.

What I missed in this production was a feeling of mystery – was it simply that the lighting was too bright? But the responsibility for the wrong kind of discomfort must rest with Pinter, who has always made me feel that his plays are a form of secret exhibitionism, that he is really on the side of the torturers.

To 17 April (0844 871 7615)