Robbie Coltrane planning to write his life story

Robbie Coltrane and Murial Gray at the opening of the new Reid Building. Picture: John Devlin

The 64-year-old star of Cracker, Harry Potter and Tutti Frutti said he had been pressured by family and friends into properly charting his life and illustrious career.

Coltrane, who was mobbed when he returned to his old stomping ground at Glasgow School of Art to open its futuristic new “Reid Building”, admitted he had found the occasion emotionally overwhelming.

Coltrane, who posed outside the new building with its first female chair, Muriel Gray, one of his oldest showbusiness friends, said he had reached a reflective stage of his life and had decided to write the biography himself - despite turning down a string of previous offers - and was even considering publishing it online.

Rutherglen-born Coltrane, who studied painting at the art school from 1968-1972, said: “I’m writing my biography at the moment. I just think I’ve lived such an interesting life. I’ve written three books, I’ve made more than 700 hours of television, I’ve made 78 movies, I’ve made a lot.

“I’ve lived in New York, I was in Britain when alternative comedy happened, I was in Tutti Frutti, I was in Cracker, I’ve been fortunate enough to be connected with a lot of really important moments in drama, and then there is Harry Potter, obviously.

“I’m writing it on my own, but I don’t want to say too much about it, it’s bad kharma to talk too much about things too early. I’m a bit superstitious.

“An awful lot of people have offered me money to do it because I’ve lived through all these interesting moments in history in the 20th century. It’s not because people love me, I know that. A lot of people I know say I should be writing all this stuff down. My son can’t believe I uses to go out dancing with Debbie Harry and that we were great chums. A friend of mine suggested that I just do it online and people can either download it or not.”

The new £50 million Reid Building stands in sharp contrast to Charles Rennie Mackintosh’s celebrated 1909 masterpiece, which is revered as one of the best buildings in Glasgow and where Coltrane himself once had a studio.

However he revealed his ongoing heartbreak at losing his collection of work he created there - in a fire at home. Coltrane said he had lost dozens of paintings and drawings in a blaze at a flat in Edinburgh - where Coltrane made his name performing at the Fringe - when he was living there in the late 1970s.

He added: “Everything was destroyed. It was horrible. I wasn’t a great painter, but I was always a good drawer and draughtsman. There was about 50 or 60 drawings lost that I would dearly love to get back.

“I still do a bit of drawing. I do a lot of charity stuff. I just get asked to send in a doodle for auction, but I always do a proper drawing for them.”

Coltrane also said that art was still not being treated seriously in Scotland’s schools, claiming it was still treated as something for children to “play” at rather than potentially pursue a creative career in later life.

He added: “I’m a great believer in art tuition at school. The impulse to pick up a pencil and make a mark is where it all starts.

“A lot of people think one of the worst things we do with children is that when they are at school we think of art as ‘play.’ We say to them ‘enough of that nonsense, now it’s now time to do some maths.’ I think that’s all wrong. It’s still not treated seriously.

“I sent both of my children to a Steiner School. They say that you shouldn’t read or write until you’re seven because it is such a strain on the brain and that during your first few years you should learn to draw and make things.

“It seems to have done them good because my son’s got an album coming out next week and my daughter’s off to drama school.”

Coltrane also became the latest high-profile Scot to duck out of the independence debate. Violinist Nicola Benedetti, actor James McAvoy, artist Jack Vettriano, tennis star Andy Murray and comedian Billy Connolly have all vowed to remain neutral until Scotland goes to the polls.

However Coltrane joked that he was forced to strip to pose as a life model after being caught imitating a tutor, Sandy Goudie. He said he was 18 when he was forced to take his clothes off - the first time anyone had seen him naked apart from his mother.

Coltrane said: “I loved his (Goudie’s) advice and he was a very funny man. I could do his voice - he had one of those booming west of Scotland voices, which you could hear at 100 yards.

“He’d come back from the pub and come clattering down the corridor towards studio one where I used to paint and he’d say ‘right you lazy student *******, get back to your easels, Maureen get your clothes off and look gorgeous, why don’t you?’

“So I would do that, walking down the corridor and then two minutes later I could hear him coming up the stairs. As way of punishment, as he knew fine what was going on, he made me take all my clothes off and get drawn by the girls. I was 18.

“A woman had never seen me naked in my life apart from my mother and there I was standing in front of a room full of people, although I had a great body when I was young, I used to play a lot of rugby.”

More than 2000 guests attended the opening of the Reid Building, a vast glass-fronted complex, which has been named after its first female principal, Dame Seona Reid, who stepped down last year.

Earlier, in his opening address, Coltrane admitted his old tutors at Glasgow School of Art would be “turning in their graves” if they knew he was opening its new building. Coltrane told the invited audience he had “hair down to my **** and a joint hanging out my mouth” when he studied painting there and admitted he would be “embarrassed” if any of them could see the work he produced as a “cheeky” student.

But he said later: “I met some of the most interesting people that I’ve ever met in my life at art school, many of whom did not go onto paint.”

Coltrane also praised American architect Steven Holl’s creation on Renfrew Street, which has been condemned by many architecture critics, as an inspiring new building - and pointed out that Charles Rennie Mackintosh’s masterpiece had been condemned by many Glaswegians when it was unveiled at the start of the 20th century.

The new opal green-coloured landmark, which has cost £50 million, has divided critics since plans were unveiled and the building began to take shape perched up on Renfrew Street, in the heart of the city’s arts and culture quarter.

It is home to the GSA’s “school of design”, as well as a gallery, an auditorium, workshops, offices and a new visitor centre devoted to the work of Mackintosh, the city’s most celebrated architect.

New York-based Holl said he was “thrilled” with the completed building - and challenged its critics to revisit their opinion by stepping inside.

He added: “It was a difficult project, we had a lot of controversy and some suspect articles written about it - people were second-guessing what it could be. I’m very excited that people can come inside it now.

“My old professor of architecture said: ‘A building must be more when you go in it than when you look at it.’ This building is really telling that story.

“You must come in and you must walk the space. That’s when you really see and feel the energy. I think the students get it 100 per cent. Other people who have already been in here get it. I would those early critics to come inside now. It’s not like any kind of glass box you’ve ever seen before.

“When you do something strong people either love it or hate it. I have a lot more people who love it now because they are in it and can use it.”