This is a general survey on the historical and modern presence of Freemasonry in Great Britain and British Freemasonry.
Masonic activity in the United Kingdom is governed by three bodies which are independent from each other. The United Grand Lodge of England has jurisdiction over Freemasonry in England, Wales, the Channel Islands, and the Isle of Man (“English Constitution” – “EC”), the Grand Lodge of Scotland over Freemasonry in Scotland (“Scottish Constitution” – “SC”), and the Grand Lodge of Ireland over Freemasonry in Ireland (“Irish Constitution” – “IC”).
Because of the historical role of the United Grand Lodge of England (UGLE) in the development of Freemasonry, the term “Regular Freemasonry”, when it is not further defined, usually refers to the United Grand Lodge of England and its recognized jurisdictions. Since UGLE is considered to be not only the oldest, but also the largest grouping of lodges, UGLE recognition (or the lack thereof) is generally the barometer by which a Masonic jurisdiction is deemed regular. UGLE provides a list of recognised Grand Lodges on its website.
(the source/read more: Wikipedia)