It is nearly 30 years since John Kani and Winston Ntshona created their play about prison life in South Africa for the small Market Theatre in Johannesburg in collaboration with Athol Fugard.

Since then, the play has toured around the world and now returns to London for a "final session," having previously played at the Royal National Theatre and at Peter Brook's Paris-based Bouffes du Nord.

And Mr Kani has become director of the Market Theatre, while Nelson Mandela returned to Robben Island to view a version of the play.

But despite the acclaim, and the end of the struggle against apartheid, the plays retains its ability to move - and shock.

Timeless

Mr Kani and Mr Ntshona are remarkable actors, who can change moods in an instant, and who manage to recreate a scene of prison hard labour on a bare stage with only a blanket and a washing bowl for props.

Playing without an interval, they manage to maintain an incredible level of energy despite being on stage for the whole performance.

When the play was first performed in 1973, it was seen as a protest play bringing into sharp focus the injustice of the South African regime.

Now it can be seen as having more universal appeal, raising the questions of freedom and brotherhood in a more general way.

Frustration

The key moment in the plot comes when Mr Kani learns that he is to receive his freedom in six months - after sharing three years together in the same cell with Mr Ntshona.

This provokes an outburst from his cellmate, whose anger at his release shows that the struggle for personal and political freedom do not always coincide.

The two end the production with a play-within-a-play. Their version of Antigone, performed before the audience as if they were the prison wardens, dramatises the conflict between freedom and order and ends with an impassioned speech that obedience to the state cannot over-ride obedience to a higher moral order.

It has the largely young audience cheering in the aisles, a sign that a new generation has embraced the lessons of the struggle in South Africa.

Political theatre never had a finer moment.

The Island is currently running at the Old Vic Theatre in London