Queen Elizabeth II becomes the oldest British monarch on 20 December 2007 - surpassing Queen Victoria's 81 years, seven months and 29 days. She is held here by her mother in 1926.

With the abdication of Edward VIII, his brother George - Elizabeth's father - unexpectedly became king. The new king is pictured with his wife and daughters at his coronation.

Princess Elizabeth plays with the penguins at London Zoo in 1938.

Princess Elizabeth served with the Auxiliary Territorial Service during World War II.

Princess Elizabeth and Lieutenant Philip Mountbatten marry in 1947.

The Queen and Prince Philip wave from the balcony of Buckingham Palace after her coronation in 1953.

The Queen takes her son Prince Andrew to Heatherdown preparatory school in Berkshire for the first time in 1968.

The Queen, who is very keen on horse racing, visits Royal Ascot with the Queen Mother in 1978.

The Queen and US President Ronald Reagan go out riding in Windsor Home Park in June 1982.

At the wedding of her son Prince Edward to Sophie Rhys-Jones in 1999.

The Queen attends the annual Chelsea Flower Show in 2006.