A heartfelt piece of theatrical correspondence from a convinced Yes voter to a man who believed in Scotland remaining part of the UK has been read in public for the first time.

But the touching Letter To David, read as part of the Great Yes, No, Don't Know, Five Minute Theatre Show staged by the National Theatre of Scotland, is also a fond tribute to the lauded theatrical figure David MacLennan.

Following Mr MacLennan's death this month, aged 65, his friend and playwright David Greig felt compelled to write the letter. It imagines a celebratory ceilidh, where the two discuss the country's future.

The show, which began its 24 hours of live theatre yesterday and continues today, is being performed at locations across Scotland, the UK and the world, and is being broadcast over the internet.

The project was co-curated by Mr Greig - a Yes supporter - and Mr MacLennan, a No supporter.

It was performed for the first time at the Oran Mor, Glasgow, where Mr MacLennan staged his now famous A Play, A Pie and A Pint series of lunchtime theatre.

Mr Greig, writer of plays such as The Strange Undoing Of Prudencia Hart and Dunsinane, thanked and honoured his colleague and friend in the letter.

It begins by relating how, last autumn, Mr MacLennan asked Mr Greig whether he could write why he supported independence. Mr Greig writes: "I think the idea was we would both write something, me for and you against, and then maybe we could use the material in the show. I had visions of a flyting … a great back and forth of ideas and wit."

This flyting - a contest of verbal abuse - would avoid "hustings claptrap" and instead would make people think and be funny.

Mr Greig writes: "At the end of the flyte there would be a bit where each of us drew our arguments back towards their reflection, where we drew our certainty into uncertainty and cast our thoughts out in such a way as to hook a moment of doubt."

He adds: "That was what I imagined. Anyway it never happened. You sent me a poem. I didn't reply.

"It wasn't that I didn't have anything to say. I had tons to say. I had a pile of stuff a mile high about democracy and social justice and paradigms for a nation state.

"I had killer arguments about Nordic energy policies and community land buyouts and walking down the street one day I came up with some real zingers about taking responsibility for ourselves and not just blaming the Tories for everything we didn't like."

Mr Greig adds that in the end, he did not reply to Mr MacLennan's poem. "And then you died," he adds.

He imagines their "brilliant flyting" becomes a tour that ends on Iona, where there is a ceilidh and the two find a bench, and listen to the music and drink whisky.

In the scene, Mr MacLennan asks Mr Greig again why he supports independence, and, in part of his answer, Mr Greig says: "I like the moment when people start to tap their feet. When a small thing suddenly and imperceptibly has the confidence to become a big thing. I like it when folk coming together and make something out of nothing. I like small places. I like a dance where everybody has to drink in the same room.

"And you'd say, 'You know, you don't need independence to do any of that.'

Mr Greig adds: "And we'd sit there and it would occur to me that all these things I valued: theatre, ceilidh, a man's a man, the tour, Iona, … all the stuff I'll be thinking of when I put my cross in the box.

"It's all stuff you made. So if I vote Yes I'll be voting for a country you gave me. And I want to say that to you. Sitting here on this bench with the sun going down over the islands, it suddenly occurs to me that I'd like to articulate that thought clearly to you. Just, you know, to say, thank you."