Queen Elizabeth mourned her late husband Prince Philip, the Duke of Edinburgh, in an understated funeral at Windsor Castle that reflected his long life of military and public service.

The Duke, who died on April 9 at age 99, was interred in the Royal Vault at St George's Chapel at Windsor Castle after a 50-minute service attended by just 30 guests due to coronavirus restrictions.

The Queen, 94, seen for the first time since his death, was dressed in mourning black, with a white-trimmed, black face mask. Close family, also masked, sat socially distanced in the historic 15th-century Gothic chapel.

The Duke was Britain's longest-serving royal consort and was married to the Queen for 73 years. He was an almost constant presence at her side during her record-breaking reign that began in 1952 as Britain rebuilt from World War II, and as its global empire began to unravel.

His death, which the family said had left a "huge void" in the Queen's life, has robbed her of the man she called her "strength and stay" during a remarkable chapter for Britain's most famous family, and in the country's history.

The coronavirus pandemic forced hasty revisions to the well-rehearsed plans for the Duke's death, code-named Operation Forth Bridge, stripping back public elements to prevent large crowds from gathering.

The ceremonial funeral from behind the stately castle walls was broadcast live on television to millions across Britain and the world.

Beforehand, a military gun fired to signal a minute's silence when his coffin – draped in his standard and topped by a wreath of white roses and lilies from the Queen – his naval cap and ceremonial sword arrived at the chapel, borne by a bespoke Land Rover hearse he designed himself.

Despite the restrictions, the stripped-down send-off for the former Royal Navy commander still combined centuries of royal protocol with pomp, pageantry – and military precision.

Members of the British armed forces, in formal dress, lined the procession route, heads bowed, as the cortege passed, as a minute gun rang out across the grounds and a bell tolled. 

The Duke's grandsons William, 38, and Harry, 36, joined the procession, in their first public meeting since a reported falling-out about Harry's shock move to California and his stinging criticism of royal life, including accusations of racism in the family. 

Harry had to quarantine when he arrived back in Britain for the first time since his move to the United States with his wife Meghan Markle, the Duchess of Sussex, last year.

The religious service was a simple affair, reflecting the wishes of the straight-talking duke, who was known for his aversion to "fuss."

In keeping with his wishes, there was no sermon, but the service reflected his love of the sea, and long association with the Royal Navy, including hymns and bible readings. 

The Dean of Windsor, David Conner, paid tribute to his "kindness, humour and humanity," and devotion to the Queen, who turns 95 next week.

"We have been inspired by his unwavering loyalty to our Queen, by his service to the nation and the Commonwealth, by his courage, fortitude and faith," he said. 

The Queen, who had been escorted to the chapel by a lady-in-waiting in the royal Bentley, watched from the chapel choir as her husband's coffin was lowered steadily into the Royal Vault by electric motor.

The Pipe Major of the Royal Regiment of Scotland played a lament, and buglers of the Royal Marines sounded The Last Post.