What and when are ‘bank’ holidays?

Many public holidays in Britain are known as ‘bank’ holidays - so called because these are days on which banks are legally closed. Most fall on a Monday.
In England and Wales there are six bank holidays: New Year’s Day, Easter Monday, May Day (not necessarily 1 May), Spring and Late Summer Holidays at the end of May and August respectively, and Boxing Day. There are also two common law holidays on Good Friday and Christmas Day.
In Scotland there are nine public holidays: New Year’s Day, January 2, Good Friday, Easter Monday, May Day (not necessarily 1 May), Spring and Summer Holidays at the end of May and the beginning of August respectively, Christmas Day and Boxing Day.
In Northern Ireland there are seven bank holidays: New Year’s Day, St. Patrick’s Day (17 March), Easter Monday, May Day (not necessarily 1 May), Spring and Late Summer Holidays at the end of May and August respectively, and Boxing Day. There are also two common law holidays on Good Friday and Christmas Day and a public holiday on the anniversary of the Battle of the Boyne (12 July).
There are holidays in lieu of those public holidays which fall at weekends. Shops, museums and other public attractions, such as historic houses and sports centres, may close on certain public holidays, particularly Christmas Day. As this varies, it is advisable to check with the individual establishment beforehand.