A "frightening" fall in the numbers of young people learning to play the trombone threatens the survival of its distinctive sound, teachers and musicians have warned.

The National Foundation for Youth Music, which advises the government, said that children are also steering clear of instruments like the French horn, bassoon and oboe.

Encouraged by parents with an eye on the price of musical instruments, many young people are opting for the violin and the flute instead, Youth Music said.

The trombone is... capable of singing itself in a very lyrical and charming way. And my wife thinks it's sexy

Roger Argente

The organisation told BBC News Online it hopes a new �800,000 campaign will restore the position of the "endangered" instruments and stave off the prospect of orchestras being forced to recruit overseas musicians.

The decline of the instruments follows the plight of the recorder, which was blamed by a recent study for turning a generation of children off music.

Price tag

Roger Argente, who teaches at Trinity College of Music in London, said most music schools had seen interest in the trombone wane over recent years.

He said: "We're just not seeing the number of applicants coming through the doors any more and it's pretty frightening."

Mr Argente said many young people could be put off by the �1,000 price tag of the instrument.

Glen Miller's success also boosted the trombone

Worries about what job opportunities exist for qualified trombonists once they graduate was another common concern.

David Sulkin, Youth Music's head of policy and programmes, said its campaign - to provide local music services with a stock of "specialist" instruments for pupils - could avoid the problem of parents baulking at cost.

He said that unless action is taken "orchestras will find it is a threat to their standards, because they will find it very hard to find the musicians they want and will have to look abroad".

"It would be terribly sad if our own country failed to continue to produce the excellent musicians that we have had in the past," he added.

'Versatile

Mr Argente - who is also bass trombonist with the Royal Philharmonic and director of Bone Lab, which encourages young players - argued that children need to be shown how much fun the instruments can be.

"It seems to me that the trombone is the instrument that is most like a man's voice and it's capable of singing itself in a very lyrical and charming way. And my wife thinks it's sexy."

Editor of The Trombonist, Tony Parsons, agreed.

He said: "It's one of the most versatile instruments of all - capable of ever so many moods.

"When the trombones get ready to play in an orchestra you know something is going to happen."

Repertoire

Mr Parsons said it was a mistake to think that the trombone has not moved on since the 1940s and the heyday of Glen Miller.

They don't have their opportunities to play in the youth orchestras and the youth bands

Roger Argente

He said: "The actual repertoire for the instrument is huge now, I mean there are actually people who make a living by being trombone soloists alongside pianists and violinists and so on."

Breathing life back into the instruments could be achieved by offering more opportunities to play them, Mr Argente suggested.

He said the youth orchestras and music system of 20 or 25 years ago helped many young musicians.

"That seems to have disappeared a lot now and I think that's also one of the reasons why we don't see as many people taking up the instrument," Mr Argente said.

"They don't have their opportunities to play in the youth orchestras and the youth bands."