RICKY Ross has killed a man. The victim, a Dundonian in his early 30s, had long hair, strong views and a loud mouth. The man was a popular figure in the late 1980s and early 1990s, appearing regularly on television, radio, in newspapers and magazines across the country. He sang well, danced badly, was loved by some and loathed by others.

The killer, though, remains unrepentant. “I didn’t really like him,” he says. “So I had to kill him off.”

It’s almost 27 years since Ricky Ross stood on Glasgow Green in front of 250,000 music fans, stuck out his jaw and let rip with a full-throated attack on Scottish Westminster Labour MPs on the biggest stage of his career at the time.

The Deacon Blue frontman was the leader of Scotland’s most prominent pop band in 1990. He and his mates hadn’t long pushed Madonna off the top of the charts with their second album When The World Knows Your Name, and had consequently been chosen to headline the biggest free music festival the country has ever seen.

The Big Day, on June 3, 1990, was an ambitious international musical jamboree which spilled out across the city, in a day-long summertime celebration of Glasgow's status as the European City of Culture featuring the likes of Big Country, Texas, The Associates, Wet Wet Wet and Hue and Cry.

It was a time of political agitation. Demonstrations and marches were commonplace, whether against nuclear weapons on the Clyde, or for the release of Nelson Mandela on the other side of the world.

Most pinned their hopes on the Labour Party to speak for a de-industrialised nation on the ropes. But not the guy from Dundee on stage with the microphone.

“I want to dedicate this to people of Motherwell and Ravenscraig who soon will have no jobs and won’t be able to afford a home to stay in,” went Ross, his rabble-rousing captured in grainy YouTube footage. “And to the people of Scotland who for the last 10 years have been lied to and sold down the river by their own people, by the leaders of the Labour Party who don’t even ask questions on your behalf down in Westminster.”

Channel 4 broadcast the whole angry thing across the UK. Down on Glasgow Green, the crowd roared their approval of the Scottish guy giving the finger to the Establishment on network television.

The clip is described on YouTube as “an anti-Tory rant”, but it is no such thing. This was a call to action, delivered 25 years before Scotland returned 56 SNP MPs in Westminster and 27 years before the clamour for a second independence referendum a few short years after the first one was lost.

It was delivered by the same man who will casually admit, in his 60th year, to having “admiration” for a succession of Tory leaders.

“That was impulsiveness,” says Ross, pondering his political maturation over lunch near his home on Glasgow's south side. “I’m not the guy at The Big Day any more. I couldn’t be. I’m much more reflective, and I think as you get older, you have different responsibilities. One of the things I feel increasingly drawn towards now is people talking to each other.

“That was a long time ago. You change a lot of your personality, and hopefully everybody does. But I wouldn’t want to change me then. I’m quite happy that I did that when I did.

“I went skiing with my 16-year-old son recently, this fearless guy, zooming off down slopes, and I can’t do that either. It’s that impulsive youth thing. Fine as a one-off, but sometimes you’re going to need a map …”

There was no map, but some might say a few roads were dug by key figures on the journey to the modern Scottish independence campaign.

Ross was pivotal in the Artists for Independence movement in the early 1990s, hosting an indy come-all-ye at his house with the likes of wife and fellow Deacon Blue member Lorraine McIntosh, Elaine C Smith, David Hayman, William McIlvanney, Edwin Morgan, Alasdair Gray, Michael Marra, Stuart Cosgrove and Liz Lochhead.

Some have gone and some remain, but their ultimate quest remains unfulfilled.

As recently as several weeks ago, Ross stated it was too early for another Scottish independence referendum. By the time he’s posing for our photographer round the back of the Glad Café in Shawlands a few weeks later, he’s changed the words to that tune.

“I don’t think there’s much choice. I said no a couple of months ago, but it’s moving by the day and by the hour. When things are moving so quickly it’s hard to put a blanket statement on things,” he says.

“The option of staying in the union could be made to seem attractive in 2014. Staying in Europe, solidarity across countries.

“But it seems all the good bits of that aren’t very visible to Scots at the moment. There’s something very different about this Conservative government and the way they’re likely to govern for what could be a long time. I think people are saying they don’t want to be a part of that.”

In 1992, Deacon Blue released the single Your Town, a brooding response to the Tories’ hold on Westminster. It spoke of a people using pictures, songs and words, doing what they could to ease the pain of life in post-Thatcher Scotland.

The song included a prophetic venomous strike at the Iron Lady. “When you’re gone they will curse you,” snarled the singer, “and raise the tide against you.”

Its sentiments could be easily transposed 25 years into the future, but their author has tethered his lash.

“People don’t like this, but I have a great admiration for Theresa May, David Cameron or whoever else it is,” Ricky says. “These people are putting themselves on the line. People might think they’re out to feather their nest or whatever, but I think they could have an easier life, and probably a more prosperous one, outside politics.”

Even Thatcher?

“Yes, and I’d say that to anyone. But I don’t necessarily have to have agreed with her.”

Could Big Day Man have made such a comment?

“No!” he says, snorting at the suggestion. “He’d never have said that. You wouldn’t have got that far with him, he’d have shouted you down.”

The band’s most recent work, though, suggests he hasn’t been silenced altogether.

Believers, their eighth studio album, was their biggest commercial success in over 20 years, entering the album charts at 12.

Its title track, a declaration of unerring hope in response to the refugee crisis, provoked a mixed reaction on the band’s social media streams with some dismissing its message as “liberal pap”.

Does he feel it’s a safe gamble to introduce contemporary politics into a back catalogue of songs so well-worn as to have become items of nostalgia in the lives of their fans?

“We are who we are,” he says. “The me you get on stage is because of what I believe. I’m a songwriter, not a politician. But I’m also the way I am because sometimes I get confused, sometimes I think out loud, sometimes I’ll react to something the opposite way I did five years before.

“But I’d never have written Dignity, or Wages Day, or Chocolate Girl or Your Town if I wasn’t someone who got up in the morning interested in what goes on in the world. That’s always been a big part of my songwriting, and I think people know that.”

The crescendo in his band’s most famous song, Dignity, about a street sweeper who dreams of saving up to buy a dinghy, sees the character thinking about home, faith and work from his boat on a faraway sea.

Ross's own home is in Glasgow with wife and bandmate Lorraine and teenage son, his three grown-up daughters now living in America, China and Australia.

Faith and work have become increasingly intertwined. Raised in the Christian Brethren, his religion and faith have shape-shifted over the years. He and his wife sent their children to Catholic school and he converted to Catholicism in his 50s.

Ross sold seven million records as a pop star, having quit his job as an English teacher. The morning of our interview, he’d been visiting St Joseph’s Primary in Clarkston, and discovered why celebrity status is incompatible with classroom work.

“I was talking about Saint Ignatius and was trying to allude to Pope Francis,” he says, smiling over the recollection. “So I asked them who the most famous Catholic was. One wee boy put his hand up and said, 'You!’ I told him if he thought that, then he was in big trouble.”

Why did he convert at a comparatively late age? “It goes way back,” he says. “When we studied the Reformation at school, I remember being excited about it, but being drawn to the other side, thinking it’s a shame they’d taken all the stuff out the churches.

“I think the spirituality of it really drew me in, and as I grew older I was drawn to what a priest friend refers to as 2000 years of spirituality. Lorraine grew up Catholic and she felt happy to return there. But I have no desire to make one religion better than the other.”

His conversion recently saw him follow in the footsteps of his late aunt Margaret and uncle Jimmy, both Brethren evangelicals who devoted their lives to spreading the Gospel in Africa.

Ross travelled to Zambia with Catholic charity SCIAF, promoting their Wee Boxes campaign and harvesting stories for his radio show.

“It was a very personal one for me," he says. “It was great experiencing something that another generation had experienced. I was surprised how basic it still was.

“But the attention wasn’t on me. Imagine this team from SCIAF coming to a village in the middle of nowhere, ‘We’re here to help you … and by the way he’s a singer.’ So I passed myself off as a radio journalist. It was much easier for me just to relate to people as someone who was taking their story and passing it on.”

His work as a Radio Scotland presenter has seen him explore home, faith and work with people from all creeds and corners.

It’s also the reason why, unlike in the run-up to 2014's referendum, he might absent himself from the public debate on indyref2, in keeping with BBC guidelines on impartiality.

“I have no plans to get involved at the moment, simply because if I do I might need to step away from my Sunday Morning show. I haven’t asked the question yet, but there’s a little bit of magic that happens in my life when I do that programme.”

The songs from his four solo albums have long been shot through with spirituality and he speaks of a new one called Only God And Dogs, inspired by a homeless Glasgow man’s devoted pet.

Some have even experienced transcendence with Deacon Blue up the Gallowgate. “A friend of mine, Father Willie Slaven, once told me at a wedding that he’d been there the night we ‘died and went to Heaven’.” says Ross.

“I had no idea what he was talking about until he explained he was the priest at St Alphonsus behind the Barrowland and came to see us on our last night round the corner.”

Since that finale in 1994, Deacon Blue have split up, reformed, released a duff comeback album in 2001 (Homesick, “the record we should never have made”), lost guitarist Graeme Kelling to cancer, toured sporadically, formed Deacon Blue Mark II with guitarist Gregor Philp and bassist Lewis Gordon joining Ricky, Lorraine and remaining original members Jim Prime (keyboards) and Dougie Vipond (drums).

After 11 years they made a new record in 2012, The Hipsters, and another two since, A New House and Believers, sparking a renaissance which has returned them to arenas like the Royal Albert Hall, SSE Hydro and Hampden Park, where they performed at the closing ceremony of the 2014 Commonwealth Games.

It has also brought them “home” to the Barras, the legendarily ramshackle venue inextricably linked with their start 30 years ago.

“We were one of many bands who people remember having special nights there,” says Ross.

“I think people just ignore all the bad bits and think about the good bits. People talk about the atmosphere, but it actually sounds very good, too. It’s a great room. And it still has that ability to punch you in the chest sonically.”

Figuratively speaking, of course. At 59, the singer appears to be in the shape of a man half his age. He’s a runner and gets gym-fit before tours, but executing pop star stagecraft doesn’t get any easier. Even if he has killed off Mr Angry.

“I love playing live, but I could easily give it up,” he says, stretching out the fingers of his hand. “But increasingly as I get older, I get aches and pains. I feel my fingers and my hand sore after playing piano.

“A lot of musicians do. Look at Bob Dylan, he can hardly move his hands and yet he obviously still loves doing it.

“I would be sad if I wanted to do it and I couldn’t physically. If someone said I couldn’t do this any more, as much as I’m sure I’d miss it miss it, I can imagine accepting it.

“You forget about gigs, they’re such passing things. I rarely remember them. But records, they’re there forever.”

Deacon Blue Live at the Glasgow Barrowlands is out now on DVD, vinyl and download. The band will play Edinburgh Castle on July 22