The flag of the County of Norfolk in England. It is the top tier of government of Norfolk County, of which Norwich is the main city.
The flag is a bi-color, gold and black field with a white ‘bend’ bearing 9 black ermine spots in alternating pairs of singles and doubles. (Yes Ermine – the weasel family animal known as a stoat. The fur of the stoat is used as trimming for ceremonial robes of royalty.) It is based on the banner of the first Earl of Norfolk from the 12th century.
This flag turned up often in demonstrations against the policies of Boris Johnson the current Prime Minister. I just thought it was kind of unique.