TV preview: That Day We Sang

As for her co-star Michael Ball: “I got sick of them begging, simple as that,” he says, laughing. “No, I’d do anything with Imelda. The time we did Sweeney [Todd, on stage] was an extraordinary time for me. I learnt more from her than I think anyone else,” he adds.

“And you seem to have forgotten it,” quips Staunton, 58, and the two chuckle.

Written and directed by Wood, That Day We Sang is a musical set in Manchester in 1969 with flashbacks to 1929, and an adaptation of her stage play of the same name. “I thought of Imelda and Michael before [they appeared in Sweeney Todd], but imagined they were out of my league,” reveals Wood.

“Imelda’s very particular and I didn’t think she’d want to do it. I don’t know why. I self-deprecated myself out of the equation. I always knew Imelda was great and took a punt in Michael,” she adds, grinning.

It’s a warm and witty tale of Tubby (Ball) and Enid (Staunton), two lonely middle-aged people who grab a second chance at life after meeting at a reunion of Manchester Children’s Choir, who made the iconic Columbia recording of Nymphs and Shepherds in 1929.

“It brings together everything I love: singing, dancing, comedy, love and chips,” explains Wood. “A musical set in 1929 and 1969, complete with tap dancing children, singing coal men and possibly a tram, was always going to be a big undertaking, but I lived in the blissful world of ignorance and I think that helped.”

The Bafta-winning writer recalls how she was 22 and living in a bedsit in Birmingham when she saw a documentary about the choir’s reunion. “Something stayed with me. The idea that maybe you have this special day and your subsequent life may not be quite match up to that memory,” says the 61-year-old.

But it was only when she was asked to write something for Manchester International Festival in 2011 that her idea for a play came to fruition.

“I thought, I do want to write about the choir and the record, but most of all, I want to write about these two middle-aged people and how it could be their second chance. Music is so powerful, and connecting with a piece of music could plunge them back into life.”

Some of the song and dance routines happen as people go about their daily business, while others take on a more fantastical element, like the Fred and Ginger routine.

“I thought: ‘Oh, I’ve not seen this on the telly’,” admits Staunton. “Why I think it’s so glorious, is it’s ordinary people being extraordinary and I think that that speaks to all of us.”

That Day We Sang, December 26, BBC2, 9pm