The government has blocked a US gallery from buying a painting by renowned British artist Joseph Wright.
Arts Minister Helen Whately placed a temporary export bar on Two Boys with a Bladder after the Los Angeles-based J. Paul Getty Museum agreed a purchase.
She said it was "of paramount importance" Wright's works were kept in the UK.
The painting dates back to the 1769 and features two children with a pig's bladder - a popular toy at the time.
Joseph Wright of Derby is considered one of the most important artists of the 18th Century and is known for his paintings of candle-lit subjects as well as scientific and industrial subjects.
Born in 1734, he trained in London but produced most of his work in Derby and as such was the first major English painter to be based outside the capital.
The J. Paul Getty Museum announced its intention to purchase the painting from a private seller in June to add to two Joseph Wright paintings it already owns.
It said the artwork had not been displayed in public since the 18th Century and was one of Wright's "most accomplished nocturnal subjects".
After taking advice from Arts Council England, the government placed an export ban until 16 January in the hope a UK buyer will come forward for the £3.5m-valued painting.
Ms Whately said: "This painting offers us a chance to learn more about his way of working and I hope a buyer can be found to save this masterpiece so it can be studied and put on public display."
Derby's Joseph Wright Gallery, which already owns 27 paintings by Wright, told The Telegraph in June it could not afford to buy Two Boys with a Bladder.
The J. Paul Getty Museum said: "We respect the British export process and look forward to a positive resolution."