St George’s Day is England’s national day – St George was named as England’s principal patron saint in 1416.
St George’s Day is listed as a flag flying day (for England only) by UK government guidance.
https://www.gov.uk/guidance/designated-days-for-union-flag-flying
The Union Flag is specified.
International Workers’ Memorial Day is a day of remembrance and action for workers killed, disabled, injured, or made unwell by their work.
It is an official flag flying day only in Scotland, not in the rest of the UK.
The saltire(s) should be hoisted right up and then lowered to half-mast for the day.
https://www.gov.scot/publications/flag-flying-on-government-buildings/
Europe Day is celebrated annually on 5 May and 9 May.
The European Union designates 9 May, the anniversary of the Schuman Declaration (1950).
https://european-union.europa.eu/principles-countries-history/symbols/europe-day_en
The Council of Europe designates 5 May, the anniversary of the Council’s founding.
https://www.coe.int/en/web/portal/5-may-europe-day
Europe Day is listed on 9 May as a flag flying day by Scottish government guidance.
The European Flag is specified.
https://www.gov.scot/publications/flag-flying-on-government-buildings/
Neither date is listed as a flag flying day by UK government guidance, although the UK remains a member of the Council of Europe.
https://www.gov.uk/guidance/designated-days-for-union-flag-flying
Guernsey celebrates Liberation Day (Lé Jour dé la Libératiaon in Guernsey French) annually on 9 May.
The date commemorates the island’s liberation in 1945 from German occupation during the Second World War.
Jersey celebrates Liberation Day (Jour d’la Libéthâtion in Jersey French) annually on 9 May.
The date commemorates the island’s liberation in 1945 from German occupation during the Second World War.
Sark celebrates Liberation Day annually on 10 May.
The date commemorates the island’s liberation in 1945 from German occupation during the Second World War.
The International Day against Homophobia, Transphobia and Biphobia is an official flag flying day only in Scotland, not in the rest of the UK.
https://www.gov.scot/publications/flag-flying-on-government-buildings/
St Helena’s national day commemorates the island’s discovery in 1502 by Galician navigator João da Nova, then serving the King of Portugal.
Anchoring in the present James Bay, da Nova named the island ‘Santa Helena’ after St Helena of Constantinople, whose feast according to the Orthodox Church falls on 21 May.
Bermuda Day first took place as Empire Day on 24 May 1902.
It continued on that day until 2018, when it moved to the last Friday of May.
It is also known as Heritage Day, celebrating the island’s culture and heritage.
Anguilla Day takes place annually on 30 May.
On 30 May 1967 the Anguillans began a revolution that led to independence from the union of St Kitts-Nevis-Anguilla.
