Britain's Queen Elizabeth II takes her seat for the funeral of Britain's Prince Philip, who died at the age of 99, at St George's Chapel, in Windsor, Britain, April 17, 2021. Victoria Jones/Pool via REUTERS

People observe a minute's silence during the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, outside Buckingham Palace, London, Britain, April 17, 2021.

The coffin of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, is taken into St. George's Chapel for a funeral service, in Windsor, Britain, April 17, 2021. Kirsty Wigglesworth/Pool via REUTERS

Cold water swimmers observe a minute's silence during the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, at the Brockwell Lido in London, Britain, April 17, 2021.

The coffin of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, is carried into The Quire during his funeral service at St George's Chapel, in Windsor, Britain, April 17, 2021. Barnaby Fowler/Pool via REUTERS

General view of the military bands parade on the day of the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, near Windsor Castle in Windsor, Britain, April 17, 2021. Kirsty O'Connor/Pool via REUTERS

Britain's Prince Charles and members of the Royal Family walk behind the hearse on the grounds of Windsor Castle during the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, in Windsor, Britain, April 17, 2021. Alastair Grant/Pool via REUTERS

Britain's Catherine, Duchess of Cambridge, looks on as she sits in a car during the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, in Windsor, Britain, April 17, 2021. Chris Jackson/Pool via REUTERS

A military hat rests on the coffin of Prince Philip as it is transported by the hearse, a specially modified Land Rover, during the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, on the grounds of Windsor Castle in Windsor, Britain, April 17, 2021. Leon Neal/Pool via REUTERS

Members of The Kings Troop Royal Horse Artillery are pictured on the day of the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, in Windsor, Britain April 17, 2021.

Britain's Prince Charles and Princess Anne follow the hearse, a specially modified Land Rover (not pictured) during the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, in Windsor, Britain, April 17, 2021. Aaron Chown/Pool via REUTERS

Members of the Royal family follow the hearse, a specially modified Land Rover, during the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, on the grounds of Windsor Castle in Windsor, Britain, April 17, 2021. Leon Neal/Pool via REUTERS

Britain's Prince Philip's coffin is carried into his funeral service at St George's Chapel, Windsor Castle, in Windsor, Britain, April 17, 2021. Danny Lawson/Pool via REUTERS

People observe a minute's silence during the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, at the Duke of Edinburgh pub in Winkfield near Windsor, Britain, April 17, 2021.

Pupils and staff of Gordonstoun School cast a wreath into the Moray Firth on the day of the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, at Hopeman Harbour, Elgin, Scotland, Britain, April 17, 2021.

People watch the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, on a smartphone, in Windsor, near London, Britain April 17, 2021.

A member of the military stands on the grounds of Windsor Castle on the day of the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, in Windsor, Britain, April 17, 2021.

People gather outside Windsor Castle during the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, in Windsor, Britain, April 17, 2021.

A woman holds a message and a Union Jack flag at Wellington Arch, on the day of the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, near Buckingham Palace, in London, Britain, April 17, 2021.

Britain's Queen Elizabeth attends the funeral of her husband, Britain's Prince Philip, who died at the age of 99, on the grounds of Windsor Castle in Windsor, Britain, April 17, 2021. Leon Neal/Pool via REUTERS

Britain's Prince William and Britain's Prince Harry follow the hearse, a specially modified Land Rover, towards St. George's Chapel, during the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, in Windsor, Britain, April 17, 2021. Alastair Grant/Pool via REUTERS

Britain's Prince Charles walks behind the hearse, a specially modified Land Rover, during the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, on the grounds of Windsor Castle in Windsor, Britain, April 17, 2021.

The coffin of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, arrives at St George's Chapel on the grounds of Windsor Castle in Windsor, Britain, April 17, 2021. Kirsty Wigglesworth/Pool via REUTERS

Members of the Royal Family follow the hearse, a specially modified Land Rover, during the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, on the grounds of Windsor Castle in Windsor, Britain, April 17, 2021.

The coffin of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, is taken from the hearse, a specially modified Land Rover, to be carried into St. George's Chapel for a funeral service, in Windsor, Britain, April 17, 2021. Kirsty Wigglesworth/Pool via REUTERS

Britain's Prince William and Britain's Prince Harry walking in the procession at Windsor Castle, Berkshire, during the funeral of Britain's Prince Philip, who died at the age of 99, Britain, April 17, 2021. Victoria Jones/Pool via REUTERS

London Black Cab taxi drivers observe a minute's silence during the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, on The Mall in London, Britain, April 17, 2021.

The coffin of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, is taken into St. George's Chapel for a funeral service, in Windsor, Britain, April 17, 2021. Justin Tallis/Pool via REUTERS

The hearse, a specially modified Land Rover, Britain's Prince Charles and members of the Royal Family walk near St George's Chapel during the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, on the grounds of Windsor Castle in Windsor, Britain, April 17, 2021.

Britain's Queen Elizabeth II looks at the coffin of her husband, Britain's Prince Philip, who died at the age of 99, during his funeral service at St George's Chapel, in Windsor, Britain, April 17, 2021. Jonathan Brady/Pool via REUTERS

Pall Bearers carry the coffin of Britain's Prince Philip, husband of Queen Elizabeth, followed by members of the Royal family entering St George's Chapel, Windsor Castle in Windsor, Britain, April 17, 2021. Danny Lawson/Pool via REUTERS

Britain's Prince Harry, Duke of Sussex looks on during the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, at St George's Chapel, in Windsor, Britain, April 17, 2021. Yui Mok/Pool via REUTERS

A child sits on the ground during a minute's silence outside Windsor Castle on the day of the funeral of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, in Windsor, Britain, April 17, 2021.

Britain's Queen Elizabeth II watches as pallbearers carry the coffin of the Britain's Prince Philip during his funeral at St George's Chapel, Windsor Castle, in Windsor, Britain, April 17, 2021. Dominic Lipinski/Pool via REUTERS