Still game: The Proclaimers at 50

“I’m older now and have to take my pleasures in moderation – at least that’s what it says here in this guide to declining years and declining nations.”

– Women And Wine, from the The Proclaimers’ new album Like Comedy

Craig and Charlie Reid turned 50 in March. For around half their lives, they have been belting out what superfan David Tennant has described as “the most spectacular, big-hearted, uncynical, passionate songs” in rare, lusty harmony as The Proclaimers and, frankly, they are wondering – in song, as in life – when all that guttural gusto is going to take its toll.

“We’re hardly trained singers but we figure that we’ll just keep singing,” reckons Charlie. “We don’t want to retire. In this game, the public retire you or you get to the stage you just can’t do it. Allan Clarke of the Hollies says he physically can’t sing any more. To be in a band like that and tour and tour then to not feel that you can do justice to the music – kind of torture I would have thought. Sad.”

Refreshingly, there is no midlife crisis in this band. Other than “maybe going out for a run and not drinking every night”, the brothers have not taken to any particular self-preserving regimen. Simon Cowell can keep his fancy vegetable shakes; The Proclaimers prefer to listen instead to that untutored instinct that has served them well for a quarter of a century.

“We don’t live frugally or like monks,” says Charlie. “We’ve looked at a couple of books over the years and we’ve taken some ideas … and rejected them. With us, we don’t want to lose what we’ve got.”

“We still have the same enthusiasm for it,” says Craig, “but now that we’re 50 there’s maybe not that many years that we can do this to the absolute peak, so we want to do as much as we can.”

The brothers did allow themselves a comfort break in 2010 following the 15-month world tour to promote their previous album, Notes And Rhymes, but now they are poised to hit the ground running again with the resumption of summer festival duties, a monster UK tour scheduled for the autumn and the appearance, like clockwork, of Like Comedy. Their ninth album continues the natural roll they have been on for the past decade, averaging one bijou beezer of an album every two years. Like Comedy is another compact, consistent collection of unvarnished Celtic soul from two of the best pop craftsmen in the business.

Things you will not hear The Proclaimers say, Part One: “Hope you like our new direction”.

“I always have a mistrust when people say that,” says Craig. “Yeah, I think you should push yourself a bit, but it should be instinctive. People have done it – David Bowie, Elvis Costello, Kevin Rowland did it well and with panache, but with others I wonder if they actually do have anything new to say or are they just getting desperate?”

The greater songwriting skill, so musicians will tell you, is not to chop and change your style but to find different melodies to fit around the same key chords.

“I’m just trying to work out how many chords Waylon Jennings ever used …” muses Charlie. “Pop music is not rocket science but pulling something original from a format that you know is tried and tested is a challenge.”

His brother agrees. “If I think I’ve written it before or heard it somewhere else, I ditch it.”

Like Comedy is a further refinement – not too refined, mind – of their craft. When asked what is the most consistently important quality they pursue in their songwriting, Charlie replies in a heartbeat: “Honesty is the primary thing. And simplicity, hopefully. I remember when we started off thinking the ideal song would be as simple as a nursery rhyme. The desire to write the same kind of song has always been there from when we started in our early twenties. For us, the benchmark would be something like an early rock’n’roll song or a Hank Williams song or a [Merle] Haggard, where you felt it was heartfelt and it was direct. We don’t want any fat round the songs. I’m not saying there never is but we try to keep it as stripped down as possible. We’re always striving for the best three-minute song we could write.”

Things you will not hear The Proclaimers say, Part Two: “Let’s write that symphony we’ve always wanted to.”

“We’re not that musical,” says Craig. “I write on the piano and I can’t even do conversions. I would never play the piano live.”

“You were never tempted to get good …” chimes in Charlie.

Next, The Proclaimers make a list of their favourite lyricists. All are time-served veterans: Kevin Rowland, Ian Dury, Joe Strummer, Morrissey, Merle Haggard. Especially Merle Haggard.

“A lot of these guys who’ve been to jail at an early age are quite damaged people,” notes Charlie, “but there was enough desire there to push ahead and he’s still writing the story of his life. It doesn’t matter if you agree with him or not – is it worth listening to?”

The Proclaimers may not have such a dramatic tale to tell but they did open their account in 1987 with This Is The Story, their raw acoustic debut written against a backdrop of unemployment and uncertainty. The brothers say they don’t listen to their old albums, but hearing some of those songs again as part of Dundee Rep’s hugely successful Proclaimers musical Sunshine On Leith was a “surreal” experience that unlocked the old emotions behind the songs. They had better steel themselves for a repeat of that sensation, as it has been confirmed that the stage musical will transfer to screen, with a film adaptation going into production later this year.

Sunshine On Leith tells a fictional tale of a soldier returning to civilian life, but would the brothers say they are still writing the story of their own lives in song? “To some degree, yeah, surely it’s got to be in there if you want to write honestly,” says Craig. “I think many songwriters are gutless, especially male songwriters. You don’t have to go to the dark places, that doesn’t make you braver to do that. But me, I feel I have to. I would write a song about virtually anything.”

“I suppose on the last couple of albums there were more anti-war songs, songs of mistrust of politicians or business,” says Charlie. “That’s fine but we don’t plan songs like that. It’s not a question of choosing it. Is this on your mind? Is this worth saying? Then you’re going to say it.”

On this album, they have wise, witty, thoughtful and touching words on ageing, language, belief systems – but mostly on love and relationships, an eternally fruitful furrow for them to plough. Like Comedy moves with ease from tender, tremulous balladry to more rambunctious irreverence and the comical, slightly caustic cultural references of current single Spinning Around In The Air.

“Generally I won’t know what a song is about until I get the first couple of lines,” says Craig. “With Spinning Around In The Air, I didn’t even know where it was going halfway through, but I was laughing as I was writing so I went with it and it makes sense eventually.”

Matt Lucas, another Proclaimers superfan, directed the video for the single, which follows the gradual drunken degeneration at a golden anniversary party.

Unsurprisingly for the Little Britain star, his first pop promo behind the camera involves a spot of cross-dressing. Surprisingly for the Reid twins, they were the drag artists, rigged out as punch-swilling old ladies.

“I did wake up at 3am on the morning of that shoot in a cold sweat,” admits Craig.

“It was like an audition for Cinderella,” notes Charlie. Then, possibly with his 50th birthday fresh in his mind, he actually utters one of those things you presumed you would not hear The Proclaimers say: “Eventually the career will collapse, but we can always go into pantomime.”

• Like Comedy is released by Cooking Vinyl on Monday.