The office of the Prime Minister is at the heart of the Westminster system of government. In any other country so central a role would be clearly defined and delineated in the constitution. But in the UK, it existed for centuries without official acknowledgement.
The first mention of the post of Prime Minister in legislation was in the Chequers Estate Act 1917, which saw the Buckinghamshire estate of Chequers bequeathed to the nation for the use of the “British Prime Minister”. The position, having no legislative precedent, was further defined as the official “now popularly known as ‘Prime Minister’”.
Through history there have been many influential ministers of state (including Elizabeth’s Lord Burghley and the Duke of Buckingham under Charles I), most agree that the first ‘Prime Minister’ was Horace Walpole. Walpole, whose ‘premiership’ retains the record for the longest lasting (1721 – 1761) would vehemently denied such a title which, in the cabinet system, was a term of abuse at a single minister who had overreached his colleagues. Walpole held the title of First Lord of the Treasury, and this was the official ‘front’ and title for every succeeding Prime Minister.
Henry Campbell-Bannerman was the first ‘official’ Prime Minister when a Royal Warrant of 10 December 1905 placed the Prime Minister in the order of precedence in England immediately after the Archbishop of York. Today’s Prime Minister has risen no higher in precedence, still ranking below members of the Royal Family, the Lord Chancellor and the Archbishops of Canterbury and York.