Precious stones from Britain's crown jewels were hidden in a biscuit tin and buried at Windsor Castle during World War II, a BBC documentary to be shown on Sunday reveals. Gems, including the Black Prince's Ruby from the Imperial State Crown, were buried under a secret exit from the mediaeval castle used in times of emergency. The operation, intended to ensure the priceless gems did not fall into Nazi hands, was ordered by Queen Elizabeth II's father, King George VI.

The Queenâu00c2u0080u00c2u0088described the crown as 'very unwieldy'. Pics/AFP