When the Amadeus Quartet disbanded after over 40 years together, every one of its members played on an instrument made by Antonio Stradivari. They were one of the most important quartets of the 20th century, and their sound was distinctive enough to be instantly recognisable in their heyday of the 1950s and '60s as the supreme English quartet.

Since the death in 1987 of the Amadeus viola player, Peter Schidlof, every one of those instruments has left England. Schidlof’s own viola – originally given to him after it was bought for what was then a world record $80,000 – was the 'Macdonald' that recently failed to sell above its estimate of $45 million after much publicity at auction in New York. Norbert Brainin, the leader, played the history-sodden ex-Gibson of 1713 that is now owned by Joshua Bell; Martin Lovett’s 1692 Bonjour cello was bought by a philanthropist who donated it to Canada’s famous 'Instrument Bank'.

The Instrument Bank is a scheme under which instruments can be donated charitably to orchestras or individuals, allowing the donor the same tax breaks they would receive for similar acts involving visual arts and paintings. There are comparable schemes in Germany (the Deutsche Stiftung Musikleben) and Norway (Dextra Musica and the Sveaas Foundation).

But there is no equivalent in Britain. As a result valuable stringed instruments are disappearing from Britain with every auction and private sale that passes, begging the question: what will our home-grown recordings and performances sound like in the future? It is a grave concern for organisations such as the Association of British Orchestras, whose mission is to make orchestral music valued as a central part of British culture.

There are currently two schemes that allow the charitable donation of musical instruments: Acceptance in Lieu (AIL, which allows the donation of a work of art to reduce the inheritance tax payable on an estate), and the Cultural Gifts Scheme (which enables 'UK taxpayers to donate important works of art and other heritage objects to be held for the benefit of the public' and receive a reduction in the income or capital-gains tax worth 30% of the value of the object). Both preclude the donation to an individual or group such as an orchestra or quartet, and this leaves British philanthropists with a stark choice. Donate an instrument directly to a player or orchestra, where it will be used for its proper purpose but receive no tax break beyond standard Gift Aid, or donate it to a museum where it will hang in a glass case with little opportunity to make any sound but receive tax relief that can amount to many hundreds of thousands of pounds.

Demand for fine instruments has always been high – at the very least they are recoginsed as a solid form of investment that outperforms, as it has done every year since World War II, the stock market by a multiple of up to 10 (in 2006, Forbes noted that in the previous 50 years top-tier violins had increased in value by over 19,400%, in comparison to the 1,800% of precious metals). But even though it is now more than a generation since Stradivari and del Gesú disappeared out of the financial reach of most players, the next tier down is now also spiralling out of control at a similar rate. This is a more serious problem than the age-old discussion about whether the rarest of instruments are worth the millions they command at auction and in private sale. These beautiful – mainly 19th century, often Italian – violins by makers such as Rocca and Pressenda are traditionally the domain of the chamber or orchestral player and are now, with prices accelerating beyond £250,000, rapidly becoming as unattainable to their core audiences as the Strads are to theirs.

This is making many players turn to modern makers for comfort. The best makers do not currently command much more than $50-60,000 for an instrument (and many much less) – a stark contrast to the near-seven-figure sums of the older makers. Arguments continue about whether or not those instruments can possibly sound as good without more than 200 years of playing and maturing of wood of their older counterparts – and many of these instruments leave the workshops of makers such as Samuel Zygmuntowicz in New York already works of art – but it is unassailable that these instruments do not (yet) have historical significance. This means they will not within our lifetime – or the lifetime of several generations to come – become instruments of historical value that even approach the value of the Serafins and Pietro Guarneris that are currently increasing at a rate of not less than 12% a year.

But how do you judge historical value? Certainly, under the so-called 'Waverley Criteria' (the three points under which the AIL scheme operates) it isn’t difficult for major instruments such as, for instance, the Viotti Ex-Bruce Stradivari of 1709, owned by the Royal Academy of Music, to qualify. It was bought in 2005 after a two-year process of evaluation, valuation, tax calculation and fundraising on the part of the RAM, and is now the central part of their Museum and Collections. Although it is played on a regular basis, it is kept for the most part in a vitrine in the Museum – possibly the best place for it, possibly not. Either way, it is the most valuable of a collection of over 250 stringed instruments, the majority of which are valuable beyond the earning capacity of any professional player, but which are nevertheless exactly the musicians by whom they should be played. The Academy lends out these instruments to their students for periods of up to a year. It is an important insight: in a profession that not only has a nebulous career path, but one whose representatives have potentially little to look forward to in terms of financial remuneration, they have appreciated that a particularly powerful form of motivation is to allow those students access to the sort of great instrument that will give them a view into the bright future of their hard-earned skills.

With the current anomalies in the tax system, though, the most negative way to look at the wonderful opportunities from which students at the RAM can benefit is as false hope. Stephen Isserlis and Nigel Kennedy both benefitted from sponsorship by the valuable work of the Stradivari Trust - a scheme that helps string players find funding to buy an instrument that they can then borrow or buy over a long period; the leaders of the Manchester Camerata and LSO both play significant instruments (one a Stradivari, one a Guadagnini, both on loan by the banker Jonathan Moulds). Both arrangements work in the spirit of understanding that the conspicuousness of such important instruments fires the imagination of both their players and their audiences that secures the future of the art form.

The Department of Culture, Media and Sport have yet to be presented with an adequate incentive to extend the same tax breaks to the donors of musical instruments directly to orchestras and individuals as they do to the visual arts, and to museums. But surely the fact that it is possible that without it within a generation the best instruments will have drained out of this country and into those that will support the direct charitable giving of musical instruments, leaving the world-leading ensembles of London and the rest of the country with diminished morale and miles from the superlative recording sound of the Amadeus Quartet, should be incentive enough to do everything possible to keep them here?

Many of these important issues were raised and discussed at the Amati Exhibition this week, for further information visit Amati.com