It also meant that the founder of the A Play, A Pie And A Pint lunchtime theatre phenomenon, founder of Wildcat and co-founder of 7:84 would not be able to witness what has turned out to be his final project. The Great Yes, No, Don't Know, Five Minute Theatre Show was conceived and curated by MacLennan with playwright David Greig as a theatrical look at the forthcoming referendum on Scottish independence.
With Greig a Yes supporter and MacLennan having come out for a No vote, it wasn't the most natural of alliances. As the two most diplomatic advocates of their respective causes in the arts, however, mutual respect has been the key to the end result.
As the title suggests, Greig and MacLennan's collaboration with the National Theatre of Scotland follows the NTS's previous Five Minute Theatre shows, in which the public were invited to submit original scripts. Selected submissions were then performed on camera and streamed live or as live on the internet to a worldwide audience.
With more than 180 submissions set to be performed across a 24-hour period, The Great Yes, No, Don't Know, Five Minute Theatre Show will also feature new revue-style sketches performed at Oran Mor in Glasgow which will tap into the sort of political satire which MacLennan cut his theatrical teeth on in the 1970s with 7:84 and Wildcat, which he led for 20 years.
"Essentially David and I have both done work around different elections," explains Greig, "and as soon as the referendum was on the horizon it was clear that someone should do something. David had come out as being quite on the No side at that point, and I was Yes, so that seemed quite interesting to both of us.
"We talked to the NTS, and agreed that whatever we did, it should be some kind of political revue show. We thought about various things and went down assorted blind alleys, but then it suddenly became really obvious that it should be a Five Minute Theatre show.
"Rather than do something that was about a troupe of actors in the central belt going round the country, it made more sense to throw it out to the public. The whole referendum is about democracy, so with Five Minute Theatre, someone can perform a song in Stornoway which can be seen by audiences in Jedburgh in a way that totally demonstrates that experience of democracy."
There is a perception in some quarters that much of the artistic community will be voting Yes. While this belief is down to a welter of activity from grassroots groups such as National Collective, the public support for the No campaign by Harry Potter novelist JK Rowling last week has changed attitudes in some quarters. Even before Rowling's statement, however, Greig took "the idea that artists are mainly for Yes with a pinch of salt anyway. There are artists who are No, but for various reasons are not inclined to put on big shows or sit on panels because they don't need to.
"On the other hand, artists who support Yes are going to be out at night at various events for totally laudable reasons.
"We aren't suggesting we can make people change their minds with this show. The whole thing about theatre is dialogue, and you can't have that without trying to understand both sides of that dialogue. David and I have had a lot of interesting discussions, but they've never had an influence on the work that we've chosen for this show, because I tell you what, theatre trumps everything. You can have an interesting piece of theatre that leans towards No, and by the same token you can have a Yes play that is total propaganda, and vice versa. In the end, we decided things on what makes the best theatre."
With passions on both sides undoubtedly running high, The Great Yes, No, Don't Know, Five Minute Theatre Show looks set to rise above some of the more simplistic and at times intolerant and abusive notions being put forward by the more extreme wings of each camp. Again, respect has been at a premium in the works submitted to the show.
"Despite their full-on inclinations," says Greig, "nobody has come out and said directly that this is why you should vote Yes or No. People seem to have come at it from all sorts of different angles, so if there were any surprises for me as I sat in a hotel bar in Fort William and read these 250 submissions over three hours, and this is going to sound trite, it was how good they were. With the sheer accretion of ideas from all these different places and different groups, it felt like I'd read an amazing play.
"When you read a submission, you're perhaps looking for certain signals, and you see that things divide roughly on the lines that the polls suggest, with probably slightly more on the No side, but that's not really the approach they took. There's an overwhelming feeling of people considering the question with a real sense of generosity. You can feel people who lean towards Yes but writing about No in order to try and find out what it's about. There was this feeling of a country talking about itself, and that was really quite moving."
The final words on The Great Yes, No, Don't Know, Five Minute Theatre Show, however, must go to MacLennan. Before he passed away, he wrote about how "this imaginative and exciting show has provoked such a huge and enthusiastic response. The submissions reflect every possible view in the referendum debate and put together they are going to make a thoughtful, passionate, provocative and highly entertaining variety show; theatre of the people, by the people, for the people."
The Great Yes, No, Don't Know, Five Minute Theatre Show will be performed at various locations across the world, and will stream live over 24 hours on June 23 from 5pm.