A heavily pregnant Duchess of Cambridge and the Prime Minister David Cameron are among the national figures gathering at Westminster Abbey for a service celebrating the 60th anniversary of the Queen's coronation.
The monarch was crowned at the Abbey on June 2, 1953 and later this morning within its ancient walls she will mark the milestone with the nation and her family.
The Duke of Edinburgh missed a royal engagement with the Queen last night because he was feeling "under the weather" but is expected to attend the service, Buckingham Palace has said.
Among the first to arrive was Labour leader Ed Miliband who walked through the Abbey's great west door.
The weather on the day of the coronation 60 years ago was dull and rainy but it did not put off the estimated three million people who lined the route of the procession.
Today spectators and guests were bathed in brilliant summer sunshine as they arrived for the formal service or lined the streets near the Abbey.
The service has been divided into the Recognition, Anointing, Homage and Thanksgiving, reflecting parts of the original Coronation ceremony.
The majestic St Edward's Crown - with which the Queen was crowned - will rest on the High Altar - the first time the heavy, solid gold, jewel encrusted crown has left the Tower of London since the 1953 coronation.
The Ampulla, the gold, eagle shaped bottle from which the holy oil was poured for the anointing - the most sacred part of the coronation - will also stand on the altar.
A flask of aromatic oil - taken from the same batch made for the Queen's coronation - will be processed through the Abbey, carried by representatives of the people of the UK , to the Sacrarium, received by the Archbishop of Canterbury and placed by the Dean of Westminster on the High Altar.
Prime Minister David Cameron is to give a reading, as will the Secretary General of the Commonwealth Kamalesh Sharma.
Actress Claire Skinner, who stars in the BBC sitcom Outnumbered, will read a poem written for the anniversary by the Poet Laureate Carol Ann Duffy.
The first members of the Royal Family to arrive at the Abbey were the Duke and Duchess of Gloucester, Prince and Princess Michael of Kent and the Duke and Duchess of Kent.
Inside the ancient place of worship the congregation were shown black and white footage of the coronation on flat screen televisions.
A re-mastered version of the BBC's coverage of the coronation was screened over the weekend on the broadcaster's parliament channel.
The Duke of Cambridge and his heavily pregnant wife the Duchess arrived with Prince Harry.
The were preceded by the Duke of York and his daughters Princesses Beatrice and Eugenie.
Also present were the Earl and Countess of Wessex and their daughter Lady Louise Mountbatten-Windsor, the Princess Royal and her husband Vice Admiral Sir Tim Laurence,.
Other royal guests included Peter Phillips and his wife Autumn, Zara Phillips and her husband the former England rugby international Mike Tindall.
Later the Prince of Wales and the Duchess of Cornwall arrived and waited for the Queen and Duke at the Great West Door.