With its startling central nudes, a Francis Bacon triptych bought by the last Shah of Iran and displayed in his wife's dazzling museum of modern art was never going to amuse the country's hard-line ayatollahs.
So when the fundamentalists seized power in the 1979 revolution, the work, Two figures lying on a bed with attendants, was one of dozens seized and sent to storage.
It has languished unseen for nearly a quarter of a century since, a victim of the sensitivities surrounding depictions of flesh, which are still regarded as indecent by today's conservatives.
But now negotiations are under way for the work, painted in 1968, to be lent to Tate Britain for display in the UK for the first time. It would form the centrepiece of a small Bacon exhibition for six months from this summer.
With Bacon triptychs now commanding as much as £6m, the show would give British art-lovers a chance to see a valuable work most will never even have heard of.
But if the loan application to Iran's Ministry of Culture succeeds, it would also be the next step in a gradual but intriguing cultural détente between Britain and a country many would regard as hostile.
Just as the American hospital erected in Bam in the wake of its catastrophic earthquake suggested hopes of a thaw in the enmity between those two countries, the potential loan of the Bacon is part of a developing relationship between Iran and the UK.
In 2001, the Barbican led the way with a season of Iranian film and an exhibition of art including works lent by the Tehran museum which it had never dared display. Last year, as part of a British Council initiative, Dundee Repertory became the first British theatre company to perform in Iran since Derek Jacobi starred in Hamlet in 1977.
Next month the British Council will open an exhibition of British sculpture at the Tehran Museum of Contemporary Art, founded by the late Shah's wife. And next year the British Museum hopes to stage the first major UK show of treasures from ancient Persia, including some of the greatest relics in Iran.
Relations can still be tricky. The Dundee actors found their performance thoroughly vetted by both the hard-liners and the liberals, with strict restrictions on men and women touching.
The sculpture exhibition was originally due to take place last year but fell foul of political sensitivities when Argentina lodged extradition proceedings against a former Iranian ambassador in Britain accused of terrorism.
But Stephen Deuchar, the director of Tate Britain who visited Tehran last month for talks, said it was clear the political climate was "conducive" to greater contact.
The groundwork for the current discussions was laid two years ago when Dr Deuchar visited the modern art museum while on a family holiday and was made warmly welcome by its director, Dr Sami Azar.
"They have got a core collection of Western art which includes some important British work - Henry Moore, Ben Nicholson and two Bacons," Dr Deuchar said. "[Dr Azar] kindly showed me this Bacon in the store and I thought it would be rather great to see it in this country in the context of some other Bacons. I hadn't even seen this one reproduced before.
"It hasn't been exhibited in this country and I don't believe it was exhibited in America apart from when it was in the Marlborough Gallery [in New York] for sale." It was in "very good condition", he added.
The work was sold shortly after it was painted in 1968 and is understood to have been in Iran by the early 1970s. Tony Shafrazi, a well-known New York art dealer, was buying works for the Shah at that time and is likely to be asked for details of how it came into the Shah's collection and the Tehran Museum of Contemporary Art.
The museum was founded with money from the country's immense oil revenues by Farah Pahlavi, the widow of Mohammad Reza Pahlavi, the last Shah of Iran. Housing Iranian art alongside works by Picasso, Monet, Dali and Warhol, it opened in 1977 with great fanfare and a guest list including Henry Kissinger and Nelson Rockefeller.
But when the royal family was deposed, the collection was seized and the more controversial works were consigned to a vault, known since then as "The Treasure".
However, some relaxation of attitudes is emerging. An exhibition of Impressionist paintings at the museum three years ago included a Renoir previously regarded as too risqué for public viewing.
Graham Sheffield, the Barbican's artistic director, who has visited Iran, said the artistic scene was thriving and artists could get "the odd erotic moment" past the censors if they were subtle enough. But Bacon's nudes were "probably a bit challenging", he said.Reuse content