Few teachers have burst into a hushed English lesson and belted out every line of The Sound of Music. Equally, few will have powered their way through “The White Cliffs of Dover” during a lesson about World War Two.

But for Denise Hodgkiss a captive audience of 11-year-olds is the perfect rehearsal for her burgeoning musical ambitions.

“When you’re teaching, it’s a performance,” the 52-year-old said. “Children are so used to multi-media, that pure chalk-and-talk teaching doesn’t engage them.”

The Year 6 teacher from St Catherine’s preparatory school, in Guildford, Surrey, is among 26 performers who made it to the second round of Musicality, a Pop Idol-style search for a West End singing star.

A chorus-line of almost 2,000 hopefuls toe-tapped and trilled through staples of musical theatre for the Channel 4 series. The shortlisted performers then spent a weekend being trained by industry professionals.

They were competing to spend three months being tutored for a one-off performance at a West End theatre.

Kerry Newton, a Cheshire-based science teacher, was one of four teachers on the shortlist, and she believes the profession’s high representation is no coincidence. “Before I trained to be a teacher, I was quiet and shy,” she said. “I could never have got up and performed before an audience. But years of standing in front of a class really helps your confidence.”

For Neil Craven, 25, a teacher at St Andrew’s Major Church in Wales primary, in Dinas Powys, Vale of Glamorgan, even lesson planning is useful preparation for the stage.

“You prepare for a lesson like you would prepare for an audition,” he said.

“You adapt the role as necessary.”

His ideal role would be Ewan McGregor’s part in the film Moulin Rouge.

Meanwhile, he is happy with a lesser-known character.

“Coming into school, I find myself stepping into role,” he said. “Monday to Friday, 9am to 3.30pm, I’m Mr Craven, primary teacher. The rest of the time, I’m someone else.”

Matthew Goodgame, a teacher at St Saviour’s junior in Westgate-on-Sea, Kent, and one-time Bernardo in an amateur production of West Side Story, believes his pupils will be surprised to see him warbling his way through “On The Streets Where You Live” on their TV screens.

“Pupils think that teachers live in the stock cupboard, and only come out to teach,” he said. “They don’t realise we have lives of our own.”

Mr Goodgame became a teacher despite nascent stage ambitions, because he felt the profession offered security.

“In 10 or 15 years’ time, I might not be able to do the splits, leap about or sing as well,” the 24-year-old said. “But I will teach just as well.

Possibly better, because I will have more world experience.”

Ms Newton, 32, teaches science at Stanney high, in Ellesmere Port. She was tempted by the structured career path that the profession offered. But, 10 years on, she has concluded that teaching is no business like show business, and moved to supply work to focus on her stage career.

“I’m a bit of a drama queen,” she said. “I sing in the classroom, and I try to get all the pupils to sing. But you can’t do a dance routine in science lessons. The bunsen burners get in the way.”

Musicality is on Channel 4 on Wednesday at 9pm. The winners will perform at the Adelphi Theatre in London on November 25. For tickets phone: 0871 230 4230