The British government is directed by the Cabinet, a group of senior government ministers led by the Prime Minister. Most of the day-to-day work of the Cabinet is carried out by Cabinet committees, rather than by the full Cabinet. Each committee has its own area of responsibility, and their decisions are binding on the entire Cabinet.
The details of the committee structure and membership are at the discretion of the Prime Minister. The Prime Minister is free to reorganize committees and their responsibilities however he or she wishes, and can appoint or dismiss members freely. The sole limitation is the requirement that Cabinet ministers must be sworn members of the Privy Council, since the Cabinet itself is a sub committee of the Privy Council.
Although there have been many changes since the Cabinet committee system was first developed in the early twentieth century, the committees for foreign and military policy, domestic policy, economic policy, and the government's legislative agenda have been more or less permanent fixtures. These and many other committees are standing committees, which have a broad remit; others are ad hoc committees, which are established to deal with specific matters. Ad hoc committees are rarer now than throughout most of the twentieth century. Many matters are now expected to be resolved bilaterally between departments, or through more informal discussion, rather than requiring the formation of a committee.
The 2015 government introduced "Implementation Taskforces" to address specific cross-cutting priorities. These are to report to the Prime Minister and Cabinet, and Cabinet approval is still required if collective agreement is needed.
Committee membership is limited to ministers, but non-ministers may attend in some cases. In particular, the National Security Council is routinely attended by senior military, intelligence and security officials. Members of the Prime Minister's office - including the Prime Minister himself - may attend any committee. The Prime Minister's attendance does not mean that he will chair the committee, despite being the most senior Cabinet member present, though he may choose to do so.
In the 2010 coalition government, each Cabinet committee included members of both the Conservative Party and the Liberal Democrats. Furthermore, the general pattern was for committees to have a Chair and a Deputy Chair, one from each party. There was a Coalition Committee, and an operational working group, to handle appeals over coalition disputes and to plan future policy.