The flag of the City of London is based on the flag of England, having a centred red St George's Cross on a white background, with the red sword in the upper hoist canton (the top left quarter).

The flag is a banner of arms, derived from the City's coat of arms with the sword symbolising the sword that beheaded St Paul who is the patron saint of the city.

[2] Some believe the sword is a dagger that commemorates the dagger of Sir William Walworth, former Lord Mayor of London, which killed Wat Tyler, leader of the Peasants' Revolt, in 1381.

A verse at Fishmongers' Hall may explain the relationship: Brave Walworth, Knight, lord mayor that slew Rebellious Tyler in his alarmes; The king therefore did give him in lieu The dagger to the city armes.

[citation needed] It can also be seen on sites outside the city that are administered by the City of London Corporation (the governing body) such as on Tower Bridge, the Animal Reception Centre at Heathrow Airport and Hampstead Heath.