‘Gaelic psalm singing grabbed me as a child’

at church,” Armstrong points out. “So, it isn’t a terribly obvious thing to do a collaboration. And also, they’ve never ever put music to the psalms before. They’ve never had any accompaniment before. So, it was a bit of a responsibility.”

Then again, he says, why shouldn’t he be allowed to try? “I felt, ‘Well, I am Scottish. It’s part of my culture and I did hear it early on.’” Plus, he had an elderly relative who, like Martin, was a precentor. That said, it was a challenge. “I really wanted to study it first. I didn’t want to just jump in and do something on the surface. I wanted to get into the bones of it and study it and analyse it.”

To do so he went up to Lewis, recorded the congregation in Back Free Church, and immersed himself in the music. “You can’t help thinking that the sound of psalm singing is very linked to nature,” Armstrong suggests. “The way they’re all singing the same thing but in different tempo and they’re all doing their own grace notes. It’s almost like a murmuration of starlings. Slightly going out of focus and then into focus.”

The first fruit of the collaboration between Armstrong and Martin was The Martyrdom Variations, which was commissioned by Diageo to be performed at Edinburgh Castle in 2014. Another piece, Ballantyne, was originally commissioned for the Lewis arts centre, An Lanntair, as part of a Creative Places Awards concert in August 2016. Ballantyne was dedicated to Armstrong’s father John who had died the previous year.

“When Craig’s father died,” Martin explains, “I said, ‘Do you know what would be nice, Craig? I would like to write a psalm tune in memory of your father.’”

“At first I wasn’t sure,” Armstrong admits. “My dad was a very private guy. But he was also a very religious guy. I think Calum connected with that, so we went ahead and did the second piece called Ballantyne which was my dad’s mother’s maiden name.”

Armstrong’s father, John, was a steelworker. “My dad worked at Ravenscraig all his life,” his son points out. “But later on – I think he was 65 – he went to study to be a lay preacher in the Church of Scotland. I thought that was quite brave of him.”

The album itself was recorded in the Caird Hall in Dundee in 2018. As well as the Scottish Ensemble, fiddler Duncan Chisholm played on Ballantyne. “The singers are from different churches,” Martin adds. “They’re from Lewis and Harris basically. Most of them would be Church of Scotland and Free Church of Scotland. They are all island people steeped in the tradition.”

AS for the soloists, Calum Iain Macleod was the former minister in Back Church that Martin belongs to. “Calum Iain, I felt, was the best guy to do it. He had that strong, almost operatic voice. But it’s also steeped in tradition.”

The other soloist is Isobel Ann Martin, who is Martin’s daughter. “She’s such a fantastic singer,” Armstrong enthuses.

“At the end of the day it is breaking a bit of new ground,” Armstrong says. “For me, it stands or falls on, does it work as a piece of music? We were trying to create something beautiful.”

Back at the start of 1998, Armstrong was telling The Herald about hanging out with Madonna and and raving about drum & bass producer Photek. It’s fair to say his situation has changed in the two decades since.

“When I had three young kids, I had to find a way to make money and to do that I became an arranger for a lot of people and I’m quite happy to have done that. My arrangements became quite well known, so that famous people like Tina Turner, Madonna and Massive Attack all wanted me which was great at the time.

“I think what happened 20 years ago was I didn’t have to take work all the time. I was able to finally choose what I wanted to do. I am not saying I’m not proud of some of the work I did before, but it was a period as a working musician.”

He is happier being his own master, he says. It also allows him to work with people like Martin on projects like The Edge of the Sea, which feel important.

“Calum is incredibly enthusiastic which is exactly what psalm singing needs at the moment. It needs someone to say, ‘Look, this is a hugely important tradition and we are in danger of losing it.’ He’s got that about him.”

And that fear of a tradition disappearing is why Martin was keen to see if it would be possible to take psalm singing out of the church in the first place.

“The bottom line at the end of the day is our tradition as we knew it and as we were brought up is on the way out,” he says. “There are very, very few Gaelic services now. I think the way things are looking I can see it dying out in the churches. “This is going to disappear, and I was wanting to do whatever I could to try and have people showing an interest in it.”

“We are acting to try to keep it alive.”

The Edge of the Sea is out now