The future of Britain’s orchestras is being jeopardised by a dramatic slump in the number of children learning to play an instrument at school.

The Associated Board of the Royal Schools of Music will tell the Government next week that unless action is taken, areas of the country risk becoming “musical deserts”.

The board’s report will show that instrument tuition is in crisis. Inner-city schools and pupils from low-income families have been badly affected, as are children in the formative five to ten-year-old age group.

Blame for the crisis is laid at the door of the previous government. The report says it ignored the fact that the high costs of instruments and tuition made it almost impossible for schools to take over when budgets were devolved from education authorities. The loss of peripatetic instrument teachers employed by LEAs has also had a devastating effect.

The music industry contributes Pounds 3.7 billion a year to the British economy. Richard Morris, chief executive of the board, warned that the slump in instrument tuition could “rot through the whole system”. There was an “obvious” threat to youth orchestras, bands and choirs and, eventually, the prestigious professional orchestras.

“Music is a pyramid with a wide base. You need a lot of younger people at lower grades. If the base is diminishing that can destroy the whole pyramid,” he said.

The board will report - in the week of the traditional Schools Prom - that provision is patchy and inconsistent across the country. Mr Morris said: “It is now economic forces and luck rather than ability that determine whether you play an instrument. Lessons are happening more in private and a greater proportion of the cost of instrumental teaching is being borne by parents. The poorer areas risk becoming musical deserts.”

Mr Morris said that the fact that so much tuition was private meant that the Government was out of touch. The board examines 330,000 candidates every year. “That makes us the only people who are in touch with the overall picture and it is pretty grim,” he said.

Chris Smith, the Secretary of State for Culture, is expected to attend the launch of the report on Monday. Representatives of the Music Education Council and the National Federation of Music Services - whose members provide instrument tuition in schools - will also be present and will call on the Government to act.

Mr Smith plans to set up a New Opportunities Fund using lottery money. He said this week that the new fund should support instrument tuition.

The Government is also considering establishing a National Schools Music Trust to raise private-sector funding. Sir Paul McCartney and Lord Lloyd-Webber have offered their support.

A government spokeswoman stressed that such funding would be additional to state expenditure, but many professionals remain unconvinced that lottery cash is the answer. Mr Morris said: “I am nervous about lottery-type capital spending. Rows of shiny new trombones and no teachers is not the answer. ”

The report will show that the threat to traditional orchestras is made more acute by the fact that less popular instruments such as the bassoon and the French horn are in the greatest decline.

Mr Morris said: “Instrument tuition got trodden on as the last government rushed into the nirvana of competition between schools. With Latin and maths that works fine, but you can’t do it with music.”