I’m in the gallery of a sound studio on a West London industrial estate, watching the recording of a play I began writing 20 years back and finished, in a form I was happy enough to see published, in 2005. Watching with me are producer, director, sound engineer and production coordinator. It’s our fifth day in. Time is tight. Today we’re trying a king.

Through the glass partition that holds the studio, a dozen or so actors, most of them household names, struggle to give rhythm and meaning to the words I’ve provided, a good half of them written by Thomas Paine himself in the course of that extraordinary life. And as I sit there, I wonder again how such a mind, such an output, such an influence, can have been suppressed into invisibility and damped into silence. Is it just a matter of that old “selective tradition” or is there something else at work? (Discuss.)

In the life of the play we’ve reached 19 January 1793, the last day of the trial of Louis XVI. A packed Convention Hall queues to vote, visitors’ galleries bay for blood, claqueurs grow drunk on their own rhetoric. With only my text and their own cultural understanding to help them, the cast have begun to conjure up the exact feel of airborne psychosis needed to persuade a contemporary audience they have been plunged into an authentic past. Robespierre, Danton, Marat shake the crazy stick and, despite Paine’s protestations, history screams for death: a mort! a mort! a mort! Death wins, but astonishingly by only a single vote, which persuades Paine to rise a second time to try a second motion from the floor. Marat seeks to have the motion invalidated on the grounds that its proposer is a Quaker, Paine screams his denial and finally silences him. But the scream and the psychopathy that follow it shape and striate Paine’s ensuing plea for mercy in ways that endorse and ape the manic craziness of what has gone before.

On the face of it, the scene’s done, we have it, let’s get on. But I’m worried. I raise the question: how can it be right that Paine should rant for revolution, when we know he always saw that revolution walked hand in hand with reason. A couple of hours earlier, we had recorded him writing: “As it is not difficult to perceive that hereditary governments are verging to their decline, and that Revolutions on the broad basis of national sovereignty and government by representation are making their way in Europe, it would be an act of wisdom to anticipate their approach, and produce Revolutions by reason and accommodation, rather than commit them to the issue of convulsions. For this is an age of Revolutions in which everything may be looked for.”

How can we now present him convulsively screeching in favour of humanity, the elimination of the death penalty and a vote for life? Surely this must find another voice: of calm, of human decency, of thought and reason. The gallery listened sagely, offered a few desultory arguments on the ground rules of drama and the need not to fall prey to bathos and anticlimax, and left me to get on with it. Five minutes with the actor and ten minutes later, we had two excellent new takes in the can and reason had prevailed.

An ordinary enough episode in the life of a working writer, you might think. And you’d be right. But it seemed then, and seems still, important enough to make an issue of. For reasons at once too many and too complicated to deal with here, I have always found revolution, as both word and process, filled with meaning and charged with importance. But it was Paine, 200 years ago, whose overarching project was revolution, who helped us see that the violence and bloodlust and mania and psychopathy commonly attached to it are frequently the revolutionary project’s worst enemies. As indeed they are to drama itself.

Trevor Griffiths’ two-part play These Are the Times: A Life of Thomas Paine is on Radio 4 on 26 July (Part 1 Common Sense) and 2 August (Part 2 Age of Reason), both 2.30-4pm