Iwitness, Finborough Theatre, London<img src="http://www.independent.co.uk/template/ver/gfx/threestar.gif"></img >

IWitness is based on the true story of Franz Jaegerstatter, an Austrian Catholic peasant who, in 1943, was beheaded for refusing to serve in the army of the Third Reich. The author, Joshua Sobol, is a former Israeli paratrooper and, when the play was performed in Israel in 2002, audiences picked up the link between Jaegerstatter's stand and the new type of refusenik that had sprung up in the Israeli army. Men who fought in previous wars for their country's survival objected to participating in what they saw as an unjust and oppressive campaign in the occupied territories.

The parallels between the situations are not exact, and Sobol doesn't pretend that there is a thorough-going equivalence. His mission is more general. He wants us to understand the statement that Jaegerstatter repeats at one point like a mantra: "When a leader breaks the rules of humanity, it is the duty of every citizen to break the leader's rules". But Sobol delivers his message in a manner that is repetitive, sometimes preachy, and handicapped by a structure that has little dramatic drive.

We encounter Jaeger statter at the end of his life, a half-naked prisoner, scrubbing pots, cleaning latrines, and refusing to save his neck from the guillotine by donning army uniform. His cell is infiltrated by flashbacks (wife, little daughter) and entered by real figures (medical officer, jailer, conscripted friends) who are determined to lure him into a compromise.

As Jaegerstatter, Mel Raido, looking Christ-like, gives a magnetic and eloquent performance. But it's a weakness of the piece that his character has achieved a state of saintly inner conviction in advance of the debates that are depicted.

Some of the points made by his adversaries are telling. Jaegerstatter says that God has spoken to him by opening his ears to the sound of the trains ferrying "undesirables" to the death-camps; but a priest points out that, if Jaegerstatter wants to bear witness, he has a vested interest in remaining alive. In addition, the prison authorities offer him a hospital job that would be confined to helping civilian victims of Allied carpet-bombing. But you never feel that these temptations are remotely seductive to him. He is also lucky in having a wife and child from whom he receives adoring respect rather than protective reproach. He smugly dismisses his former mistress.

Instead of the bracing whiff of tested holiness, this well-meaning play gives off the odour of sanctimony.

To 27 January (08704 000 838)