After 20 years in the entertainment business, The Proclaimers, otherwise known as Craig and Charlie Reid, have a special place in the Scottish psyche. Their songs, from the joyous exuberance of ‘I’m Gonna Be (500 miles)’, to the celebratory yet quietly melancholic ‘Letter From America’ and on to the heartfelt and achingly emotional ‘Sunshine on Leith’, are inspired by real life as it is lived. On reflection, it seems remarkable that, given the sense of drama their songs evoke, their work hasn’t formed the centre of a musical until now. The bright idea to place them in this kind of spotlight came from writer Stephen Greenhorn, who, in collaboration with Dundee Rep, has created Sunshine on Leith: the Musical.

The boys themselves are in the middle of a splendid run that goes way beyond the theatre, with a new album and tour in the offing as well as the recent Comic Relief revival of ‘500 miles’ topping the charts and giving them their first ever UK number one. His feet still firmly on the ground, Craig reflects on the last few months: ‘It’s great - everything seems to have come together at once. We had this album planned for a while, and we got the call from Comic Relief about the song last September, and we said “yeah, we’ll do it”. As to Sunshine on Leith, we knew the musical was going to happen a couple of years ago, but it’s terrific it’s happening now. We said okay to Stephen thinking it was going to be a couple of nights in Dundee. Since then, it’s just got bigger and bigger as a show, with this big tour and so on. We were delighted. We really didn’t think it would be as big as it’s turned out.’

And how are they coping with being back in the spotlight? ‘It’s 20 years since the first album came out, so we knew it was going to be a big year for us, but there’s been more than we thought. The chat show circuit has been easier. The first time we did it, it was pretty overwhelming. Suddenly we had a record out and it was a hit, so everyone wanted us, and it was almost too much for us. This time around it’s been very enjoyable actually.’

How does Craig feel about Greenhorn’s comment that he was drawn to the project by the drama of their songs? ‘There’s a really wide subject matter to our material; they aren’t all love songs by any means. Maybe that lends itself to theatre as well. We try and write as honestly and directly as we can about life the stuff we write is fairly personal.’

On the face of it, Greenhorn, a political writer, whose narrative in Sunshine on Leith centres on two soldiers who are having trouble readjusting to life in their home town after returning from action, might not seem an instant match with The Proclaimers, yet Craig says their recent work has been more political. ‘There’s more political stuff with the new album that we’re going to start recording in a couple of weeks than there’s ever been before. It’s not by design, that, it’s just the way the songs come out, but this new one is definitely more like that. There’s more about the Iraq war, which we mentioned on the last album, there’s also a song about Cash for Honours, one about racism . . . there’s about half a dozen of them.’

Sunshine on Leith, Dundee Rep, Wed 18 Apr-Sat 12 May, then touring.