The modern Cabinet evolved from one of the earliest forms of government in Britain which has its roots in the 11th century - the Privy Council. The Privy Council was a group of prominent men, mainly from the church, aristocracy or gentry who offered advice to the monarch. It was originally formed from various councils used by the Norman and Plantagenet kings. By the 15th century the Privy Council was large, with about 40 councillors, dealing mainly with administrative matters. Because of the unwieldiness of such a large council, monarchs often had a smaller circle of advisors. Often this smaller circle of advisors included men who held the 'Great Offices of State' or the monarch's 'Principle Secretaries'.
The constitutional changes of the late 17th and early 18th centuries helped develop the smaller informal circle of advisors into the beginnings of the modern Cabinet. Charles II re-established the Privy Council on the restoration of the monarchy in 1660, but relied on a smaller informal committee for advice. However, the 1701 Act of Settlement, by granting the crown to Sophia of Hanover and her Protestant heirs, made the monarch's small informal committee of advisors even more important due to the fact that George I, the first Hanoverian king under the terms of the Act of Settlement, could not speak English. The monarch's small committee of advisors therefore gained more executive power and importance at his expense.
From the start of the 18th century parliament and government evolved. Sir Robert Walpole (1676-1745), considered to be the first modern Prime Minister (although he would not have recognised the term), held occasional meetings with the king's ministers. William Pitt (the Younger, 1759-1806) eventually established the right of the Prime Minister to ask ministers to resign, a key part of the Prime Minister's power. The 1832 Great Reform Act with its redistribution of parliamentary seats, established the need for the Prime Minister (and the Cabinet he had selected) to have the confidence of parliament as well as the monarch. As the electoral franchise expanded during the 19th century this became more important. Conventions that shaped the Cabinet during the 20th century were developed - collective responsibility and Prime Ministerial control.
When David Lloyd George became Prime Minister in December 1916, the secretariat of the Committee for Imperial Defence, under Sir Maurice Hankey, became the nucleus of a new Cabinet Office and served a War Cabinet of five members. With the return of peace, Lloyd George replaced the small War Cabinet with a traditional Cabinet of 20 members. At its first meeting on 4 November 1919 the new Cabinet decided to retain the methods of record keeping used by the War Cabinet. In the early 20th century the term 'Prime Minister' to describe the role of chief minister began to be used. The use of 'Prime Minister' and its position as head of the government was formalised by the 1937 Ministers of the Crown Act.
Membership of the Cabinet increased from five in the late 18th century to 17 by the end of the 19th century and over 20 by 1915. Up to 1916, a letter written by the Prime Minister to the monarch was the only record of the decisions of Cabinet. In 1916 the War Cabinet Secretariat and the post of Cabinet Secretary were created. This formalised the way Cabinet business was conducted and recorded; its papers form the records that can be viewed through this website.