An all-girl choir from a city school has won the chance to sing at this summer's musical extravaganza, Prom on The Close.

The group, known as The Six, won a Last Choir Standing-style sing-off in front of an audience of shoppers in Cabot Circus – despite only five of them taking part in the contest.

Group member Becky Brown, aged 17, said the choir, which was founded and run by pupils of Redland High School, saw themselves as "the underdogs" and never expected to win the competition.

She told the Post: "It's such a fantastic opportunity. We've only ever done school concerts before. We thought we were the underdogs; just taking part was an honour."

Already enthusiastic members of the school choir and accomplished instrumentalists, the girls came together two years ago to perform madrigals in the school production of A Midsummer Night's Dream.

They won the sing-off despite being one member down because one of the girls was on holiday.

The judges – consisting of top orchestra Emerald Ensemble leader Roger Huckle, and Alison Noble, the mother of ex-head chorister of Bristol Cathedral Choir, Tom – said that The Six had "brilliant sound and great intonation".

The Prom, which is sponsored by Ashfords Solicitors and supported by the Post and sister paper the Western Daily Press, takes place in the grounds of Clifton College on July 4 and this year is even more special as it is also part of Bristol University's centenary celebrations.

Runner-up in the sing-off was Partsong, a Bristol-based a capella group led by James Vaccaro. The judges said they were "lots of fun".