WHEN he was first approached about a musical based on Take That music, Tim Firth was “strongly against it”.

“Gary (Barlow) and I talked about it 20 years ago and I said ‘Don’t do it. You have to protect your legacy, and shows like that can be dangerous’. They can look lazy and opportunistic. I did one, Our House, and was desperately trying to find a musical in a load of Madness songs. I said it was the only one I’d ever do,” says the writer of films Calendar Girls and Kinky Boots and TV comedies Flint Street Nativity, Neville’s Island and All Quiet on the Preston Front.

“I was still saying ‘Don’t do it’ when Let It Shine was on TV. I thought it was a very tricky thing to pull off,” adds Tim. “I was convinced it was too big an ask to find a band that could sing, dance, act and be funny.”

Let It Shine was BBC1’s search for five lads to appear in The Band, a musical co-produced by Take That, featuring their songs. The winners, chosen by viewers, were AJ Bentley, Nick Carsberg, Curtis T Johns, Yazdan Qafouri and Sario Solomon, collectively Five To Five. Gary Barlow, who was head judge, has since admitted it was a risk - but it paid off. Within two hours of tickets going on sale in March, The Band office took £2 million, making it the fastest-selling tour ever.

“Once I realised it wasn’t the band trying to be Take That, it got me thinking about the other half of the equation - the fans,” says Tim. “This was a chance to write about a bunch of girls who are 16 and love ‘the band’.”

The show, which Take That have called a ‘thank you to our fans’, is about growing up with a boyband. For five teenagers in 1992, ‘the band’ is everything. Twenty-five years on, they’re reunited as 40-something women, trying once more to fulfil their dream of meeting their heroes.

The most intense friendship in life are the ones we make at school. Even if we drift apart from our ‘best friends forever’, it feels like they’re always with us, yet with that comes a sense of loss.

“We don’t forget the people we meet early in life,” says Tim. “For those years at school, we’re forced together and so much happens in such a short time. It’s a time like no other, and friends share that. These are very different friendships to the ones we make in our twenties. The Band is about those friendships and how, when we’re older, we look back at the promises we made when we were 16 and realise that actually we have kept to them. We just need to step to one side to see that.”

Tim, one of Britain’s most successful screenwriters and dramatists, grew up in the same Cheshire village as Gary. They have been friends for years and first collaborated on hit musical The Girls. Writing The Band has been a different process. “It was working with pre-existing material, but as soon as we put the songs in, a peculiar thing happened,” says Tim. “Love songs took on a new poignancy - instead of romantic love, the words were about loss. They took on an unexpected relevance.”

Nothing evokes a memory quite like music. “When you hear a song again, everything you once felt is absorbed in it - the friends you had, who you were in love with, where you were,” says Tim. “That song becomes partly owned by you and you’ll hear it differently to anyone else. It might take you to a happy time, or it helped you get through the night.

“The band’s songs are the fabric of these girls’ lives, and they become the time travel between their younger and older selves. The show is about friends, not the band. The title doesn’t even refer to the band - it refers to a concert wristband and the significance it takes. It’s basically Lord of the Rings in a musical,” he smiles.

Two years ago, Tim and Gary premiered The Girls, their warm, poignant, funny musical based on the story of the Rylstone and District WI’s world-famous nude calendar. Tim also wrote hit film Calendar Girls, starring Julie Walters and Helen Mirren, and the subsequent play, and in each interpretation he captured beautifully the spirit of friendship between a few middle-aged women who set out to buy a sofa for a hospital waiting-room and ended up on a US chat show, having raised millions for Leukaemia and Lymphoma Research.

“I seem to be drawn to female friendships. I really must get around to writing about men sometime,” laughs Tim.

* The Band is at the Alhambra, October 17-28. Call (01274) 432000.