Some of the world's most important paintings may be lost to the nation because there are no funds available to keep them here following the purchase of two works by Titian for £100m.
The latest artwork poised to join the exodus of masterpieces is St John the Evangelist by the Italian Old Master Domenichino. Despite being in the UK for the past 100 years, the painting is likely to leave the country – a situation described as "lamentable" by one art expert – because funds that could have kept it in Britain were used last year to help the National Gallery buy the Titians.
Some experts fear the Titian purchases could tie up art funds for the next five years. Last week the culture minister Margaret Hodge slapped an export ban on the Domenichino, which was bought by an anonymous bidder in December for £9.2m, on the grounds of its "outstanding aesthetic importance".
The export ban will give UK institutions two months to raise the money to buy it. But there is no money left in the public art pot after £50m was raised by the national galleries of England and Scotland to buy Titian's Diana and Actaeon. The galleries are committed to raising another £50m in the next two years to buy a second Titian, Diana and Callisto, from the Duke of Sutherland. The National Gallery of Scotland announced on Friday that the two paintings will spend almost a year in America to raise money.
Professor David Ekserdjian, of the Government's Reviewing Committee, which examines art sales, said: "It is the best work by the artist remaining in private hands and its departure from the UK would be lamentable."
St John the Evangelist, painted in the 1620s, had been owned by the Christie family who run the Glyndebourne Opera festival, since the 19th century. The £9.2m it raised at auction in December was a record for the Baroque artist.
At the same auction a Raphael drawing – Head of a Muse – which has been in Britain since the 1930s, sold to a US collector for £29.2m, a record for any work on paper. An export ban has also been placed on it. The head is a draft drawing for a Vatican commission and is considered a "unique record of Raphael's original artistic vision".
A National Gallery spokeswoman said: "It is inevitable that putting resources into the acquisition of Diana and Actaeon may result in having to turn down other opportunities, but the painting is so important that we are willing to accept this."
1. Raphael's Head of a Muse The "exquisite" drawing from 1510 – a preparation for a commission by Pope Julius II – looks likely to be on its way to America after being bought for a record £29.2m, even though "every possible effort should be made to raise enough money to keep it in the country".
2. Turner's Pope's Villa at Twickenham One of Turner's most important works is already in America after an export ban last year failed to find any institutions willing or able to pay the £5.4m the 1808 painting was worth.
3. Domenichino's St John the Evangelist It will be "lamentable" if this £9.2m work from 1621-29 left the country after more than 100 years, according to the Reviewing Committee. Lamentable, but likely.
4. Titian's Diana and Actaeon A six-month campaign persuaded the public, the Scottish government and the Heritage Lottery Fund to part with £50m to buy the Old Master's work from the Duke of Sutherland last year. Fundraising is due to start shortly to raise the same sum for the companion painting, Diana and Callisto, by 2012. Both were created between 1556 and 1559.
5. Turner's Blue Rigi One of the finest watercolours by one of Britain's greatest painters, an 1842 view of a Swiss mountain, was saved in 2007 after the Tate raised £4.95m.