When should the Union flag be flown at half mast?

The Union Jack flag at Whitehall is flown at half mast following the death of Queen Elizabeth II.

users have claimed that Union Flags are flying at half-mast outside

Downing Street Union Jack at half-mast after death of Queen Elizabeth II | AFP

Flag lowered to half-mast at Windsor Castle after Queen Elizabeth II's death

Government Buildings to Fly Union Flag All Year | NTD UK News

Are Union Flags flying at half-mast across UK? As netizens worry for Kate and Charles

Gulf War veteran has been ordered to take down Union Jack flag

British flag removed from EU Council building

EU flag sales in UK at half mast after Brexit vote

American regions that still have a Union Jack 🇬🇧

Flag at half-mast over the UK parliament

Union Jack at half mast at the Tower of London and bell being tolled 96 times on Fri 9th Sept 2022

Flags At Half Mast Over London (1941)

Kate Middleton drama: Flags at #Buckingham Palace were not recently flown at half-mast #royal #uk

Union flags fly at half mast in tribute to the late Duke of Edinburgh | SWNS

The Union flag flying at half mast at the local Church, due to the recent passing of the Queen.

Union Flags return to full mast as official mourning for Queen Elizabeth II ends

Union Jack flags @ halfmast

Union flag taken down outside EU Council building in Brussels