A Swiss foundation has unveiled what it said was an earlier version of the Mona Lisa painted by Leonardo da Vinci, although some experts said the claim was unlikely.

Photographers crowded round today as the curtain was pulled back to present what is claimed to be an early version of Leonardo da Vinci’s Mona Lisa.

A foundation says it will prove to the world today that Leonardo Da Vinci painted an earlier version of the Mona Lisa – a claim doubted by at least one expert on the multifaceted Renaissance artist.