CERTAIN theatrical characters become like exiled acquaintances, encountered on the occasional visit home. They are recognisably the same but altered by the intervening years and by life in a strange country.

John B. Keane's Bull McCabe, the protagonist of The Field, now in its umpteenth incarnation in Ben Barnes's production at the Gaiety, has been on the go for a little over 30 years. Every few years we have an intense evening in his company. Each time, he does and says exactly what he did the time before. But, even as he does so, we can see that he has lived, in the intervening years, an unsteady life. The Bull is now, if not quite a reformed character, then certainly a much altered and much more sympathetic one.

I didn't see Ray McAnally's original Bull but from all the descriptions of it in print, it seems to have been a terrifying creation, full of rage, menace and dark power. Beginning with Ben Barnes's first production of the play in the Abbey in 1987, this elemental force has become gradually more explicable. In that production, Niall Toibin began the process of making the Bull almost a tragic figure, caught between the values with which he grew up and the new ethic of a changing, industrialising Ireland. Then, in Jim Sheridan's film version, Richard Harris gave psychological and political meanings to the Bull's violence, locating him both as a failed father and as a vestige of atavistic nationalism.

Now, in Ben Barnes's second visit to the play, the Bull, embodied in a compelling and consistently intelligent performance by Pat Laffan, has been entirely humanised. He is no longer an obscure force rising up from the depths of post Famine Ireland but an infinitely weary Atlas trying to hold a dead world on his shoulders. His violence the brutal murder of an interloper who tries to buy a field, the Bull believes to be his by right is now an act of desperation and defeat, proof, more of impotence than of power.

There are very good reasons for this shift of emphasis one of them external to Keane's text, the other an integral part of it. The first is that the Ireland in which the play now finds its audience is a world away from the one in which it was written, and not just because murder is no longer an almost unbelievable act of sacrilege against the order of things but a mundane occurrence. When Keane wrote the play, the Bull's world was still present all around him, still dangerous and frightening.

Now it is definitively gone. It is an ancient temple that we visit, not as people who might become a sacrifice on its altar but as curious archaeologists, able to contemplate in some comfort the peculiarities of a distant civilisation. Since we're not afraid of the big, bad Bull, we need to replace fear with understanding.

The other reason is that for all its continuing force, The Field has weaknesses. Midway through the second half, after the climactic moment of the murder, it loses some of its grip. All that is left is what doesn't happen nobody spills the beans, the Bull gets away with it, justice is not done. As a reflection of reality, this is brave and truthful but as a piece of drama, it is less than satisfying.

The strength of this production is that it solves both of these problems in the same way by making the Bull much more remorseful, and much more obviously haunted, than he has been before. Pat Laffan has the physical presence to ensure that the Bull is no less domineering. But, from the start, he plays the large scale of the Bull's physique against the small scale of his emotional and psychological horizons. His rage for control is in inverse proportion to the amount of his world that he actually controls.

In all the universe there are just three things on which he can exercise his power a field, his doltish son Tadhg (Pat Kinevane) and the miserably sycophantic Bird O'Donnell (Mark O'Regan). And none of them is worth it. The field is jest a bit of ground.

KINEVANE and O'Regan, for their part, manage, quite brilliantly, not just to play their own parts but to become reflections of the Bull's doom. As the agents and objects of his attempts to control the world around him, they are so obviously inadequate that everything he does seems, from the start, to be assured of ultimate failure.

With that knowledge, the murder, instead of being the climax of the play, becomes much more openly pointless. Barnes plays up the essentially accidental nature of the killing, so that, instead of being triumphant, the Bull's later acquisition of the field is merely the meaningless playing out to the end of a game that has gone hopelessly wrong. Grief and horror, not glee, are etched into Laffan's face in the last scenes, giving them a poignancy and a dramatic complexity that they have not had before.

Such revelations of psychological complexity, in a play that once seemed more like a folk tale of clashing elemental forces, more than justify the decision to give an old war horse another run. In a society that has changed as much as ours has over the last 30 years even the most familiar parts of that culture have, it seems, the capacity to catch the light at ever different angles.