The annual Trooping the Colour ceremony in honour of the Queen's official birthday is taking place.
The Queen is attending but her husband, the Duke of Edinburgh, is missing the central London parade as he recovers from abdominal surgery in hospital.
More than 1,000 soldiers and horses are taking part in the traditional display of pomp and pageantry.
The Queen was cheered by the crowds as she travelled to Horse Guards Parade in a vintage carriage along The Mall.
In place of Prince Philip, the monarch invited her cousin, the Duke of Kent, to join her for the short journey in the glass coach.
Built in 1881 as a town coach for the Lord Mayor of London, the carriage was purchased for King George V's coronation in 1911, and has been used in royal weddings, including the Queen's marriage to Prince Philip in 1947 when she was still Princess Elizabeth.
The military parade comes after the Queen's Birthday Honours list was published.
Royals on horseback
Other senior royals arrived in carriages before the Queen made her entrance at Horse Guards ParadeThe Queen took the royal salute as members of the royal family looked on and the Trooping ceremony is now taking place.
Taking part on horseback are the Duke of Cambridge, Colonel of the Irish Guards, the Prince of Wales, Colonel of the Welsh Guards, and the Princess Royal, Colonel of the Blues and Royals.
The Prince of Wales and the Princess Royal are on horseback for the paradeThe Duchess of Cambridge is making her last public appearance before the birth of her first baby, due next month, and earlier travelled along The Mall in a horse-drawn carriage with the Duchess of Cornwall and Prince Harry.
Thousands of people lined the streets to watch the royals, including the Duchess of Cornwall and the Duchess of Cambridge, go byThey were followed by the Duke of York, with his daughters Princesses Beatrice and Eugenie, and the Earl and Countess of Wessex, with their daughter Lady Louise Mountbatten-Windsor.
Thousands of people, including friends and family of the soldiers taking part, are lining the streets for the celebrations.
Prince Harry travelled to the parade with the duchesses of Cambridge and CornwallA 41-gun salute will be fired in Green Park to mark the Queen's official birthday.
The royals will then gather on the balcony at Buckingham Palace to watch the traditional RAF flypast, which will include Spitfire, Hurricane and Lancaster aircraft, and a display by the Red Arrows.
Traditional preparationsThe display of pomp and pageantry originated from traditional preparations for battle.
Colours were carried or "trooped" down the rank so that it could be seen and recognised by the soldiers.
In the 18th Century, guards from the royal palaces assembled daily on Horse Guards to "troop the colours" and in 1748 it was announced that the parade would also mark the sovereign's official birthday.
The Household Cavalry are among the members of the Armed Forces taking partThe Colour being paraded on Horse Guards this year is that of the 1st Battalion Welsh Guards, who recently returned from service in Afghanistan.
The Coldstream Guards, who this week laid to rest one of its soldiers whose remains had lain buried beneath the sand dunes of a Dutch beach for more than 200 years, are also taking part.
The Queen's actual birthday was on 21 April, when she turned 87.
Prince Philip, 92, has been at a private clinic in London since 7 June when he had an exploratory operation on his abdomen.
He is expected to remain in hospital for a further week, followed by a period of convalescence of about two months.
