It sounds like one of those improbable Blue Peter projects. A nuclear submarine out of a washing-up liquid bottle? No problem. A musical instrument made with cardboard tubes, a piece of string and two polystyrene trays? Why, within two hours we can have you playing at London’s Royal Festival Hall with the world’s leading contemporary string quartet.

Unlikely as it may sound, that is the prospect that almost 3,000 pupils will face next month at the Festival Hall, where they will form the “drumpet orchestra” under the instruction of the American musicologist Dr Craig Woodson and join the Kronos Quartet in a performance.

Over the past three years Woodson and the Kronos have introduced thousands of American children to the joys of cheap but serious music-making. Woodson has also undertaken similar educational projects with the Cleveland Orchestra, the Los Angeles Philharmonic and the National Symphony Orchestra in Washington. This is Britain’s introduction to his unique and unconventional methods.

One of the world’s great enthusiasts, Woodson - who studied and later taught at the University of California, Los Angeles - made his first instrument when he was 13 and has a zeal to share his passion for music. “I want young people to discover the joys of making music and to kindle an intellectual curiosity about it,” he says.

“Hopefully working with professional musicians and participating beyond listening is going to give them a new way of looking at things and offer them an access to music which they might otherwise be denied.”

Woodson has now patented about 140 different home-made instruments, but the “drumpet” that students will be invited to build at the Festival Hall is the top of the range - a percussion, string and woodwind instrument all in one. He has the cardboard tubes made with an industrial-strength glue but the other elements that participants will be handed from his bag of tricks when they arrive are all items found in everyday life.

“It should take about 20 minutes to construct, and I explain how it is based on instruments from around the world all of which have elements which were eventually adapted to make up the modern orchestra. They look fragile but they are surprisingly sturdy. I’ve had letters from kids who say they have kept them for years,” Dr Woodson says.

The drumpet is constantly being refined and the next version will be upgraded to include a spoon, but he explains the mechanics of the current model.

“The stringed part is based on an Indian instrument with a scraper for a bow, and the long cardboard tube is based on a soprano didgeridoo. In Australia they use wax at one end, but we use a bandage. There is a little dome on the other end which comes from the top of one of those fast-food chain drinks containers.

“Then there are two plastic trays attached to the tube with a band, and each tray makes a different percussive sound to give different tones.”

After the drumpets have been manufactured, the Kronos Quartet will play for 20 minutes before the instruments are brought out again for the “play-along” as the audience is first coached and then asked to perform two contemporary works by Raymond Scott and John Oswald for string quartet and massed drumpets. A question and answer session follows with the four Kronos members, and the audience are invited to take away their instruments and continue practising.

The event is part of a week-long festival on the South Bank celebrating the 25th anniversary of the Kronos Quartet. In recent years the educational element has become an essential part of the group’s work.

David Harrington, leader of the quartet, says: “Craig has a unique ability to get to the heart of music and bring out the joy of it. He is an inspiration.”

They first met five years ago at a concert in Ohio. “I took a box of my home-made instruments to David and I gave him a violin which was made with a coathanger and dental floss,” Dr Woodson recalls.

“When he played the instrument it sounded like a sick child, so he asked me to show him how to do it. He was used to a $40,000 violin and mine cost 99 cents. He was fascinated and suggested working together.”

Harrington was looking for a musical education project with which the Kronos could get involved. “It is a scandal what is happening in American schools,” he says. “We are producing a generation that has virtually no access to musical instruments.”

Woodson describes sad visits to American schools where there is no music teacher or where music teaching consists of 30 minutes every other week. They are alarmed to hear that the recent report by the Associated Boards of the Royal College of Music suggests Britain’s schools face a similar decline.

“That is so short-sighted,” Dr Woodson says. “Music enhances children’s self-esteem and can raise their grades across the board. In my work I emphasise the history of instruments and how they developed in different cultures. There is maths and science in there, too, because instruments are basically tools. I hope the kids get a lot out of it.”

And then, of course, there is how it will look on the CV in years to come:

“May 1998: performed at the Festival Hall with the Kronos Quartet” is definitely something to blow your own drumpet about.

Kronos for Children with Dr Craig Woodson takes place at the Royal Festival Hall on May 30. Tickets are pound;5, which includes the cost of instrument-making materials