"Where there is discord, may we bring harmony ...” Thirty years after Margaret Thatcher denounced the Winter of Discontent her words have taken on a new and surprising resonance - in choirs. Cheaper than therapy, more inclusive than sport and a whole lot more fun than an hour on the cross-trainer, choirs are relieving the credit-crunch blues of stressed-out professionals.

All over the UK, amateur choirs are packed. What's more, in a contemporary spin on Industrial Revolution philanthropy, choirs are springing up in white-collar bastions. The international law firm Eversheds runs a choir at its Cardiff branch, and at the Barbican in London last summer five financial firms staged The City Sings. Among them was the UBS Choral Society, founded in 2005 and now 80-strong. It meets on a Tuesday lunchtime, for an hour, rehearsing anything from Fauré's Requiem to Queen's Bohemian Rhapsody.

Pam Kilmister, a business analyst in equity research, is the choir's chairman. “When you're doing 10 to 12 hours as a working day, it's nice to get away from your desk for an hour,” she says. “You have to think of nothing else because the singing is tough. You go back to your desk invigorated.”

UBS has no audition and singers don't have to read music - typical of the new, user-friendly choirs. It's a weekly oasis of no-pressure, collective achievement. “We do songs we may never have heard before but by the end of the session we're singing the whole thing through,” Kilmister says. “I come out feeling elated.”

There is science behind this euphoria. Singing releases endorphins - just as exercise or eating a bar of chocolate does. It's also physical; warm-up exercises relax the body and it improves posture and breathing, even relieving asthma in some sufferers. A study by Harvard and Yale universities concluded that singing increased life expectancy by developing a healthy heart and mental alertness.

Of course, Kilmister and her colleagues work in a sector with little to sing about right now. After two rounds of redundancies last year, the UBS choir has lost four members. Can a singalong boost morale?

“Yes, in these tough times the choir is really important,” Kilmister says. “If you're feeling down in the office because people around you are dropping like flies, it's nice to go somewhere and see that there are people still working and those people come together and sing their hearts out.”

John Rutter, one of Britain's leading choral composers and conductors, leads regular “Come and Sing” days. They attract all sorts, he says. “Members of the House of Lords, teachers, nurses, the police. A choir is a tremendous social lubricant for a community.” And for individuals it can be a great social leveller. “You all get shouted at - or, rather, encouraged - just the same,” he says, recalling a singing day at the Middle Temple (one of the Inns of Court) attended by the country's legal elite. “You have to submit to the same discipline even if you're a High Court judge used to dishing it out Monday to Friday. On Saturday you have to sit there and take it.”

Choirs have existed for years; what's changed is what they sing. The current champs of BBC One's Last Choir Standing are the Welsh male-voice gang Only Men Aloud!, who triumphed with a version of All By Myself (last heard in Bridget Jones's Diary, delivered by a tired and emotional, pyjama-wearing Renée Zellweger). Pop, gospel, show tunes, Afro-Cuban rhythms or classical - anything goes these days.

On a Wednesday night in Guildford almost 200 singers ride a wave of endorphins. They belt out the Zutons' Valerie, fingers clicking and hips swaying. Rock Choir was founded in 2005 by Caroline Redman-Lusher, a singing teacher. From a notice in her Farnham coffee shop, one choir of 70 has grown to almost 800 people, aged from 6 to 70, rehearsing across the South East.

Oozing feel-good vibes, Rock Choir is less Metallica, more Magic FM. “We sing classic, good songs: Aretha Franklin, Annie Lennox, Queen. The ones you put on in a sports car, press play and go for it,” says Redman-Lusher, a classically-trained musician who arranges the harmonies and accompanying dance steps.

“There's definitely a physical buzz,” Jan Glynn says between verses of Stevie Wonder's Signed, Sealed, Delivered I'm Yours. A property developer who joined Rock Choir three years ago, Glynn says that the choir provides therapy in tough times. “Even if you come in and you've had a crappy old morning, you bounce out.”

Find a choir at www.choirs.org.uk.

See also www.rockchoir.com

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