TWENTY years ago, Sir James MacMillan, the leading Scottish composer, composed one of the sensations of the Edinburgh International Festival.

Delivered not long after providing the opening fanfare for the new Scottish Parliament, MacMillan’s speech at the festival (EIF) confronting ‘Scotland’s Shame’, or the persistence of anti-Catholicism, caused much controversy.

His speech, which said Scotland was guilty of a ‘’sleep-walking bigotry’’, led to a wave of comment and analysis, but now the composer says he looks back on the speech, and its aftermath, with some mixed feelings.

As he prepares to have his 60th birthday celebrated at this year’s EIF in a series of concerts, including the premiere of his new 5th Symphony, the composer feels that there is “unfinished business” in Scotland addressing the issue.

He said: “I have been thinking about this, I realised people might want to talk about [the anniversary]. It does seem like a long time ago, another lifetime ago: my 40th birthday. Has anything changed? I don’t know. There is still the same lack of decision about whether it was an important issue, or not.

“It kind of divided people, some said: ‘Yes, this is an issue worth raising’, and other people said it wasn’t an issue, it was an old story, not a problem anymore.

“Then all the experts came on board, as you would expect and desire - sociologists, historians, writers, clergy, politicians, and they lined up on two sides too, and nothing was settled.”

He added: “I can’t decide whether it was worth it, or not.

“It is unsettled business, but maybe we have all moved on, and there are new toxicities that are even more divisive for society that are even more difficult to heal and to solve, so maybe the agenda has changed.

“However, it cannot be ignored that even last year [in March], Government figures came out saying that so-called hate crimes north of the border, Catholics were disproportionately targeted: 57% were against Catholics: why would you want to run away from those figures?

“I mean, I can understand: I want to run away from those figures because they are horrific. It just means there is unfinished business there. But I am glad it is not me that is trying to finish it, these days.”

He added: “I have parked it, I have put it to one side, which is odd because at the time it was very pressing issue for me. Perhaps we have all moved on to more pressing issues....life needs living and music needs written.”

MacMillan noted: “I double-checked the title: it was not just Scotland’s Shame, it was also ‘Anti-Catholicism as a barrier to genuine pluralism.’ So that was my concern, that a minority in Scotland might think carefully about what its role was in society, and that Scotland should care about all its citizens.”

The premiere of the composer’s new, hour-long symphony, No.5, subtitled La Grand Inconnu, will be at the heart of the EIF’s celebration of his life and work.

He said: “I am very proud about it, I’ve been coming to the Edinburgh Festival since I was a teenage boy. I remember the first time, it was probably 1977, even before I started university, and I saw Mary Queen of Scots by Thea Musgrave, I heard The Rite of Spring, pieces by John Tavener, all these things - I saw [Yehudi] Menuhin play Beethoven.”

La Grand Inconnu is a French term, ‘The Great Unknown’, which is often associated with the Holy Spirit, the composer said.

MacMillan, who is 59 until July, added: "In English it means 'the great unknown', but it can mean something completely different. It is for two choirs, and an orchestra, and there are four soloists.

"It is a exploration and reflection on spirit, the Holy Spirit for for example.

"There are texts, I have a little [Saint] John of the Cross in there. But generally it is words, and sounds, that got it going: for example the Hebrew word for breath is 'ruach', and the Greek word is 'pneuma', and the Latin word is 'spiritus', so you can see where I am going with that."

The second movement is is inspired by words in each language for water, and the final movement ruminates on the words for fire.

He added: "Why the Holy Spirit? Well I suppose its the most mysterious thing about the faith, I suppose.

"All of Christianity is a mystery, I suppose, but the idea of this third person, its the one we cannot really relate to. We can get the Father, and we can get the son, because he was an historical figure, but the Holy Spirit: what is that about? So there is a mystery there that fascinates me.

"Also, I think for secular people, it is what is most fascinating about the Trinity. What is this spirit thing? It is not just the arts world, I think society in general is rediscovering spirituality, the spirit, it means a lot to people, especially in the world of music.

"People talk about music being the most spiritual of the arts: they're not talking about conventional religion, like me, but they mean something by that, and they use that for the impact music has on their life, which is transformative. So for all those reasons I thought it was a good way to go."

On reaching 60, he said: "I just keep going, there is too much to be getting on with. I don't feel old, so I don't think about it.

"I am walking my youngest daughter down the aisle in July, so I need to get healthy for that.

"Her twin brother was married last year.

"It is a momentous year: but life goes on - I am in the middle of writing a Christmas Oratorio just now, which won't see the light of day until Christmas, 2020. I will be sitting in sweltering July, writing this: quite an odd feeling."