Prior to 1834, the Bank of England observed about thirty-three saints' days and religious festivals as holidays, but in 1834, this was drastically reduced to just four: Good Friday, 1 May, 1 November, and Christmas Day.
In 1871, the first legislation relating to bank holidays was passed when Sir John Lubbock introduced the Bank Holiday Act 1871 which specified the days Easter Monday, Whit Monday, First Monday in August and Boxing Day for England Ireland & Wales. Scotland was treated separately because of its separate traditions; for instance, New Year or Hogmanay is a more important holiday there.
Good Friday and Christmas Day were not specified for England, Wales and Ireland because they were already recognized as common-law holidays.
It was then not until exactly a century after the 1871 Act that the Banking and Financial Dealings Act 1971 was passed; it is still in effect today. The current bank holidays are those specified in the 1971 Act; also listed are two additional bank holidays introduced since 1971, which are deemed bank holidays by the legal device of a royal proclamation every year. This same device is also routinely used to shift bank holidays that would otherwise fall on a weekend. (This is why diaries often have to resort to the phrase 'subject to confirmation' since theoretically there might not be such a royal proclamation.) The two additional days now routinely added since 1971 are New Year's Day and the Early May Bank Holiday (except in Scotland, where they are the Spring Bank Holiday and Boxing Day).
The 1st Monday in August holiday was retained by Scotland, whereas we have the last Monday in August in England.
The bank holiday for NI mentioned above is to commemorate the Battle of the Boyne.
