Since 1917 it has been customary for the Sovereign to send a message of congratulations to a British subject celebrating his or her 100th and 105th birthdays, and those thereafter.

On 4 August 2000, Queen Elizabeth The Queen Mother celebrated her 100th birthday; and that morning a congratulatory card from her daughter, The Queen, was duly delivered to Clarence House.

Although using the same card as those sent to centenarians throughout the country, it included a personal message written by The Queen and signed 'Lilibet', the pet name given to her as a child by her parents.

This 100th birthday message therefore celebrates the centenary of a much-loved member of the Royal Family, and is also a rare example of The Queen acting as both daughter and Sovereign.