If you think that the finest art in Britain is on display at Tate Modern or the National Gallery, think again. Increasingly, many of the best works are in the hands of private collectors, who do not always make their treasures accessible to the public. The New Statesman has tracked down some of the most important artworks nestling in the private residences and offices of collectors, aristocrats and City businesses, where only the most privileged can see them. This trend is on the rise; with public galleries increasingly priced out of the art market, more and more work will disappear from public view.
Public interest in visual art has never been greater. Crowds flock to blockbuster shows at the major galleries: "Velázquez" drew record crowds to the National Gallery in London late last year, and the Tate galleries attract nearly two million people annually. At the same time, however, immensely wealthy individuals and companies are pumping money into the art market and inflating prices. In one sale earlier this month, Sotheby's made £95m in just three hours. And on 8 February, Christie's recorded a landmark sale, with Francis Bacon's Study for Portrait II going for £14m. With prices like this, it is impossible for public galleries to get a look-in.
The latest significant work to be snapped up by a private collector is J M W Turner's The Blue Rigi, which has been described as one of the greatest watercolours in art history. The painting fetched £5.8m at auction last June, making it the most expensive British watercolour ever sold. An export ban was placed upon it, and now the Tate and the Art Fund have launched a public appeal to raise the additional £2.45m they need to prevent the painting from leaving the country.
Without extra public help, The Blue Rigi would consume the Tate's entire annual acquisitions spend of approximately £5m. The British Museum, Britain's second most visited free attraction, has less than £1m per year. In contrast, the Metropolitan Museum of Art in New York spends more than £50m. In 2005, the Met lavished roughly £26m of its budget for that year on a single masterpiece - Duccio di Buoninsegna's Madonna and Child. This is twice the annual budget of the four biggest-spending British art institutions put together.
The problem is likely to get worse in the near future. Gordon Brown has threatened a 7 per cent reduction of grants to museums and galleries for three successive years. Charles Saumarez Smith, director of the National Gallery, says that successful exhibitions such as "Velázquez" and Tate Britain's current show of work by Hogarth might become a thing of the past if the situation remains unchecked. "If the government reduces its baseline support by the amount it is saying it will, then the public programmes of museums and galleries - their exhibitions and education programmes - will be damaged disproportionately," he says. "I cannot believe that the Chancellor wants this to happen."
His views are echoed by David Barrie, director of the Art Fund. "Do ministers understand the extent of the problem facing museums and galleries? And, if so, when are they going to get around to doing something about it?" he asks. "Rather than discussing budget cuts, the government should be urgently looking at ways to increase their spending power."
The Clive of India Flask
According to experts at the Victoria and Albert Museum, where this item spent more than 40 years of its life, the 17th-century jade wine flask is a "technical masterpiece". Once owned by the military commander Clive of India, it disappeared from public view after being sold at Christie's in 2004. Its new owner, the pre-eminent Middle Eastern collector Sheikh Saud al-Thani, tried to export the £3m flask to Qatar, but changed his mind when the British government placed an export stop on the item. Its present whereabouts are unknown.
Morning: a pastoral landscape and Evening: a pastoral caprice with the Arch of Constantine (both 1651) by Claude Lorrain
Both of these items are in the private collection of the Duke of Westminster, which is thought to be kept at the family's Eaton Hall seat, near Chester. Although the duke sometimes lends his paintings to public exhibitions, these two works have not been seen in the past seven years. In 1971, the art historian Denys Sutton wrote to the then prime minister Edward Heath with a list of privately held paintings that he believed should be saved for the nation if ever they came on to the market. These Lorrains were on the list. Members of the public cannot make an appointment to see them, according to the duke's official spokesperson.
Costermonger's Stall (1992-97) by Michael Landy
This flower-filled installation was included in Charles Saatchi's infamous 1997 exhibition "Sensation" at the Royal Academy. It is now at the private London residence of the collector Anita Zabludowicz, who bought it at Christie's in 2002 for £23,900. It has divided critics and the public, and was vandalised when exhibited at Tate Modern in the year prior to its sale.
Elements of Blair's Grave (1805) by William Blake
Blake illustrated Robert Blair's poem "The Grave" with 20 watercolours, 19 of which were put up for auction in New York last year. The paintings were considered the most important works by Blake ever to be auctioned. The decision to split up the collection caused huge controversy in the art world, but two parts ended up in the London home of Alan Parker, head of the public relations firm Brunswick.
White Abstract (Sir Norman Reid Explaining Modern Art to the Queen) by Keith Coventry (1994)
This work also appeared in "Sensation" as the witty finale. Though it is all white, the figures in the painting are clearly visible "through" the brush strokes. The Austin/Desmond gallery bought it in 2002 through the Fine Art Society; ultimately, it was acquired by the collector David Roberts, who doubles as chief executive of the property developer Edinburgh House Estates. The piece currently hangs in his private residence in London.
Billingsgate (1859), an etching by James Abbott McNeill Whistler - Clifford Chance collection
Clifford Chance, a City law firm, is famed for its collection of prints, which includes work by Whistler, David Hockney and Barbara Hepworth, but the art is kept principally for the firm's employees and clients. It has been buying British 20th-century prints in particular for more than 15 years, with an annual purchasing budget of £20,000 and a total of roughly 800 pieces. "It was supposed to be something to make the office more tolerable," says the firm's partnership secretary, Keith Salway. "People can sit in meeting rooms for hours on end."
Queen Henrietta Maria with Sir Jeffrey Hudson (1633) by Sir Anthony Van Dyck - Fitzwilliam Collection
Lady Juliet Tadgell, who is based just outside Canterbury, loaned many of her works last year to the Chrysler Museum in Virginia, but these have now returned to behind locked doors at Bourne Park. The collection also includes masterpieces by George Stubbs and Joshua Reynolds, a particularly fine copy of Audubon's rare Birds of America, and important pieces of Rockingham porcelain. A Bourne Park spokesperson said that the artworks were rarely lent out to public exhibitions.
Turning the World Upside Down III (1996) by Anish Kapoor - Deutsche Bank collection
Deutsche Bank owns about 50,000 works of art worldwide and has one of the best post-1960s collections of works of art on paper. At its London headquarters, the company has 52 rooms named after artists. On the eighth floor, the "Bacon Room" is home to three lithographs of bullfights by the artist and a catalogue of his work. One of Damien Hirst's spot prints nestles in the lobby near Kapoor's sculpture, which the bank claims has become like "a second logo". Deutsche Bank says as a "general rule" it does not let the public view its art collection.
How to see private collections
Although you may never be able to see the artworks listed above and on the next page, the public has the right to view thousands of paintings, sculptures and items of furniture - including works by Turner, Blake and Van Dyck - held in private collections. Those who inherit important works of art, buildings or land are exempted from inheritance tax if they agree to allow "reasonable public access". The items are registered on a list held by HM Revenue and Customs. More than 19,000 works of art are on the list, and the scheme has saved private collectors roughly £1bn in tax since it was introduced in 1982. Here's how to get your money's worth:
Visit http://www.hmrc.gov.uk/heritage  and search for the artwork you want to see. Alternatively, you can search by region on a clickable map.
The name of each artwork is listed along with contact details for viewing. If the item you want to see is not on public display, you can arrange a viewing.
The owner is obliged to offer you an appointment on the day you want, or offer a slot between 10am and 4pm on any one of at least three weekdays and two Saturdays or Sundays within the following four weeks.
You may be asked for identification, and the owner is allowed to make a reasonable charge.
If you have any problems, phone the HMRC inheritance tax team on 0115 974 2490. Remember, it's your right to view these works of art - you've paid for them.