William and Kate join the Queen for Garter Day

Prince Charles travels with the Duke and Duchess of Cambridge. Credit: Press Association

The Queen and wider Royal Family gathered at Windsor Castle this afternoon for the annual Garter Day celebrations.

After lunch in the castle's Waterloo Chamber, the members of the Order processed to St George's Chapel for a service.

Today's procession at Windsor Castle. Credit: Press Association
(L to R) Princes Andrew, Edward, William and Charles process to St George's Chapel, Windsor Castle. Credit: Press Association
The Duchess of Cambridge shares a moment with her husband. Credit: Press Association

The Order of the Garter is the oldest and most senior British Order of Chivalry, founded by Edward III in 1348. Membership is a personal gift from The Queen.

In addition to the monarch and heir to the throne, there can be up 24 Knight or Lady Companions of the Order at any one time.

The Duke of Cambridge became the Order's 1000th member in 2008.

The Duchess of Cambridge watches proceedings with the Countess of Wessex. Credit: Press Association

Today two new Companions were installed: Dame Eliza Manningham-Buller, former Director General of MI5; and Sir Mervyn King, former Governor of the Bank of England.

Members are entitled to put 'KG' (Knight of the Garter) or 'LG' (Lady of the Garter) after their name.

New members Dame Eliza Manningham-Buller and Sir Mervyn King. Credit: Press Association