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.
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.
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.
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.
The Falkland Islands celebrate Liberation Day annually on 14 June.
The date commemorates the liberation of the islands from Argentine military occupation in 1982.
The Birthday of the Prince of Wales is listed as a flag flying day by UK government guidance.
The Union Flag is specified.
https://www.gov.uk/guidance/designated-days-for-union-flag-flying
Under his Scottish title (Duke of Rothesay), the Birthday is also listed as a flag flying day by Scottish government guidance.
The Scottish Saltire is specified.
https://www.gov.scot/publications/flag-flying-on-government-buildings/
The British Virgin Islands celebrate Territory Day annually on 1 July.
On this date in 1956 the islands became a separate British Overseas Territory.
The Isle of Man celebrates Tynwald Day (Manx: Laa Tinvaal) annually on 5 July, unless this date falls on a Saturday or Sunday.
In this case Tynwald Day takes place on the following Monday.
The Birthday of HM The Queen is listed as a flag flying day by UK government guidance.
The Union Flag is specified.
https://www.gov.uk/guidance/designated-days-for-union-flag-flying
The Birthday of HM The Queen is also listed as a flag flying day by Scottish government guidance.
The Scottish Saltire is specified.
https://www.gov.scot/publications/flag-flying-on-government-buildings/
Turks and Caicos celebrate Constitution Day annually on 30 August.
The date honours the first constitution of the islands, adopted on 30 August 1976.