Scotland Yard investigators announced Tuesday the results of the probe into the fire, saying that the electric device had been accidentally left switched on for two days on the 19th-century tea clipper, leading to the disaster on May 21.
The ship had been undergoing an extensive 25 million pound ($50 million) restoration program due to end in 2009. Half the wooden planking and masts had been removed, which probably saved the ship from complete destruction, although the metal hull has been damaged.
Police had considered the fire on the famous ship as "suspicious."
The Cutty Sark was built in Dumbarton, near Glasgow, in 1869, and was named in honor of a witch from a poem by the Scottish poet Sir Walter Scott.
Initially the ship ferried tea from China to Britain and then wool from Australia. She was placed in dry dock in Greenwich in 1949 and later opened to the public, receiving up to 15 million visitors a year from all over the world.
