British Prime Minister David Cameron said a giant diamond, the 105-carat Koh-i-Noor, his country forced India to hand over in the colonial era will not be returned.

Speaking on the third and final day of a visit to India, Cameron ruled out handing back the Koh-i-Noor, now on display in the Tower of London. The diamond, presented to Queen Victoria in 1850, had been set in the crown of the current Queen Elizabeth’s late mother. If the Duchess of Cambridge, the wife of Prince William, eventually becomes queen consort, she will don the crown holding the diamond on official occasions.

When Elizabeth II made a state visit to India to mark the 50th anniversary of India’s independence from Britain in 1997, many Indians demanded the return of the diamond. One of the world’s largest diamonds, some Indians — including independence leader Mahatma Gandhi’s grandson — have demanded its return to atone for Britain’s colonial past.

“I don’t think that’s the right approach,” Cameron told reporters. “It is the same question with the Elgin Marbles,” he said, referring to the classical Greek marble sculptures that Athens has long demanded be given back.

“The right answer is for the British Museum and other cultural institutions to do exactly what they do, which is to link up with other institutions around the world to make sure that the things which we have and look after so well are properly shared with people around the world.”

“I certainly don’t believe in ‘returnism,’ as it were. I don’t think that’s sensible,” he said.