When the Second World War broke out at the beginning of September 1939, Princess Elizabeth, later Queen Elizabeth II, and her sister, Princess Margaret, became evacuees. Evacuees were children sent out of big cities – where air-raids were likely – to the safety of the countryside. The Princesses’ destination was Windsor Castle.

During the war, Windsor Castle once again became a fortress, designed to keep those inside safe. Loudspeakers were installed to warn of approaching air-raids, while basements were transformed into shelters. To ensure that the Castle fell into darkness at night and was invisible from the sky, black-out blinds and curtains were put up.

Efforts were also made to protect the Royal Collection. Precious drawings were sent away to the National Library of Wales and historic documents in the Royal Archives were moved out of the Round Tower and into the Castle’s underground areas. Perhaps most crucially, the Crown Jewels, including the magnificent Imperial State Crown, were transferred for safekeeping to Windsor Castle from the Tower of London.

Princesses Elizabeth and Margaret were kept busy throughout the war. Along with the rest of the country, they were encouraged to ‘Dig for Victory’ by growing their own fruit and vegetables, which they did at their allotments at Windsor.

In October 1940, Princess Elizabeth made her first public speech – an address to the children of Britain and the Commonwealth, broadcast during the Children's Hour radio programme. Less than two years later, in April 1942, she carried out her first official public engagement – an inspection of the Grenadier Guards at Windsor Castle, having recently been appointed their Colonel.

In addition, the Princesses took part in a series of Christmas pantomimes intended to raise money for charity. A production of Cinderella in 1941 was followed by Sleeping Beauty and Aladdin. The final pantomime, staged in 1944 and given the playfully quirky title, Old Mother Red Riding Boots, was devised by the Princesses themselves with the help of Hubert Tanner, Headmaster of the Royal School at Windsor.