Never can the Market Theatre have witnessed a more powerful performance than that of David Keller in Simon Rae's Grass: The Life of John Clare, on Sunday evening.

Keller conveyed successfully all the tortured anguish of a genius born at the wrong time, into the wrong class and married to the wrong woman.

This was the passion play of John Clare, a true story modernised for a contemporary audience while allowing essential, telling glimpses of an older tale.

It was as though Rae, a presenter of Radio 4's Poetry Please programme, did not believe enough in Clare's own poetry to allow it to speak on its own terms. This was most notable in the closing recital of I Am, one of Clare's finest laments.

The 19th Century lyricism was stripped away, together with Clare's own strengthening belief in God.

The modern Clare had been turned into a road protester, along the lines of "Swampy", and the eloquence of an old litany had been modernised out of existence, towards contemporary incoherence and "credibility".

Clare's suffering in the mental hospital was still there to see, and the horrors endured by our modernised poet closely matched real incidents in the life of his Victorian shadow.

When, too infrequently, we could hear Clare's actual words, the audience was reminded that here was the last great Romantic, in a school that had included Shelley, Keats and Byron.

The social protesters of the 19th Century are mainly footnotes in history, but Clare is still revered as a great poet for the words he saw published.

Mr Rae, I fear, did not recognise this fact when writing his play.

Gary Bills-Geddes