A royal flag at Windsor Castle won't be lowered after Prince Philip's death

• Prince Philip, 99, died at Windsor Castle on Friday.
• A royal flag at Windsor Castle hasn't been lowered, due to royal family tradition.
• The flag represents the British monarchy and flies at full mast whenever the Queen is at Windsor Castle.

A royal flag outside Windsor Castle will not be lowered following Prince Philip's death on Friday.

While a Union flag outside Buckingham Palace was lowered on Friday afternoon, the royal standard flag outside Windsor Castle remained at full-staff, according to the BBC. The move was in step with official protocol.

The royal standard flag represents the monarchy and is flown whenever Queen Elizabeth is in residence at Windsor Castle. The flag is never flown at half-staff.

Buckingham Palace said on Friday that Prince Philip, aged 99, passed away peacefully, launching a mourning period of flags flying at half-staff across the UK.