The year is 1609 and Galileo, a brilliant mathematician, uses the newly-invented telescope to observe the heavens. A year later his observations provide the first experimental proof that the Earth goes around the Sun, not the other way around.

At first all goes well, and Galileo becomes something of a celebrity. But then he falls foul of the Inquisition, is forced to renounce his theories and is sentenced to lifetime arrest in his own home, where he is looked after by his daughter who has become a nun.

That, in a nutshell, is the story of Galileo. Brecht’s play is characteristically powerful and didactic. In this production, the sinister Cardinal Inquisitor (Patrick Romer) wears red gloves to signify blood on his hands, just as the Pope puts on red gloves to signify that he is willing to sacrifice his old friend Galileo.

Translator and playwright Mark Ravenhill saves the production from being too dry by bringing out the humour in the absurdity of the situation, in particular the attitude of the church.

The play opens with Galileo, played by Ian McDiarmid, teaching his protégé Andrea (Matthew Aubrey) about the movement of heavenly bodies. His use of pencils and apples to show why a person standing on a revolving Earth does not fall off is worthy of any modern communicator.

McDiarmid’s Galileo is a mischievous eccentric, using humour to survive, making the transformation when he returns from the Inquisition a broken and aged man quite shocking. But the mischief comes back at the end, when he manages to get his secret writings smuggled out.

Finally a word on the minimalist set, which uses screens like great boards of graph paper, complete with a few equations. It is very modern, and yet quite appropriate.

DIANA DEAL

Where: Theatre Royal, Bath
When: Until Saturday