The most valuable cut diamond ever to be offered at auction has gone on display in London.

The Pink Star is expected to sell for more than 60 million US dollars (£48.4 million).

The auction record is currently held by the Oppenheimer Blue, which fetched 50.6 million Swiss francs (£35 million) at Christie's in Geneva, Switzerland, last year.

At 59.60 carats, the Pink Star is more than twice the size of the Graff Pink - the 24.78-carat gem which holds the pink diamond auction record.

The Pink Star sold for more than 83 million US dollars (£52 million) at an auction in Switzerland in 2013, but is back on the market after the sale defaulted.

David Bennett, Sotheby's jewellery division's worldwide chairman, said: "At a time of unprecedented demand for the finest in coloured diamonds, I am delighted to be bringing this magnificent stone back to the market.

"The extraordinary size of this 59.60-carat diamond, paired with its richness of colour, surpasses any known pink diamond recorded in history."

The diamond is on display at Sotheby's London offices before its sale on April 4 in Hong Kong.

Mined by De Beers in Africa in 1999, the 132.5-carat rough diamond was cut and polished over a period of two years.