IAN Pattison usually takes about a month to come up with an episode of his classic sitcom, Rab C Nesbitt.

However, his latest theatre play, A Terrible Beauty, based on the final few days in the life of Irish revolutionary Michael Collins, has been percolating in the brain for the best part of three years.

This suggests Pattison, who mined the seam of biography to excellent effect with his satire on Tommy Sheridan and again with the life of Scots psychiatrist RD Laing, is not only passionate about his latest project but slightly obsessed.

"You only have to walk through that door and you are caught for life," says the writer of the subject of the Irish civil war. "It's so utterly absorbing."

A Terrible Beauty will be staged next week in Oran Mor's A Play, A Pie And A Pint strand, and stars George Docherty, John Kielty and Gavin Jon Wright. But why Collins? Govan-born Pattison did not grow up with a yearning to discover more about the Easter Rising.

"I have a pal in Ireland, Steve, whom I visit and I realised he takes the trouble to understand Scottish politics, so I decided I would bone up on Irishness. He gave me a book by Irish poet Patrick Kavanagh called The Green Pool, an autobiography, and one little section covered the effect of the war of independence on his town. This provided an aperture for me to get into the wider area of the civil war. There is something so beguiling about Irish history, Irish people and Irish writers to which Scots are susceptible. Certainly this Scot anyway."

Pattison read extensively on the events of 1916-22, Ireland's attempts to break away from British control. He also realised the anniversary of the Easter Rising is imminent. And, of course, the Scottish referendum is close too. It all resonated. "The nearest parallel to Scottish independence is the Irish case, and it seemed worth examining, in a non-partisan way."

The writer came up with the idea of a play set in the last two days of Collins's life in West Cork. "The play is about crystallising an issue. It is not over-fanciful to imagine Collins would have had extended conversations with senior anti-Treaty Republicans about a groundwork for peace. That gives you the debate."

Pattison travelled to the subject's birthplace in West Cork. "I met a couple of civil war experts, the effect of which was to both plunge me into despair and invigorate me. I thought, 'How dare I even attempt to cover this subject?' but I took on board what I heard and learned."

Collins fascinated the writer. "The first thing to say is not everyone is a huge Collins admirer. But he seemed to embody a great many of the virtues we find valuable and worthy of respect. He was hugely charismatic, slept four hours a night, and worked constantly. And he never lost the common touch. While de Valera was feted in America, Collins was fighting the war, organising intelligence, riding around on his bicycle, distributing money and taking his life in his hands."

Collins had worked in London as a young man and considered a life in America. But his Nationalist instinct kicked in, and he returned to Ireland. The freedom fighter was part of the failed uprising in 1916 at Dublin's GPO building and selected to be shot. "Incredibly, the way he avoided this was to wait until the officer's back was turned and simply walk over from the queue of condemned men to the line of uncondemned. Nobody noticed."

The story highlights the drama and the aura surrounding the man, which Pattison finds fascinating. And it suggests, therefore, that the new play will be powerful.

"Whatever happens with this play, I will still be reading up on Irish history," he says. "I can't give up on it. It's a bit like falling in love. You don't realise it's happening. But when you're in, you can't get out."

A Terrible Beauty, Oran Mor, Glasgow, September 8-13.