The factors governing the prime minister's selection of ministers

The factors governing the prime minister's selection of ministers- The greasy pole

The power to appoint, reshuffle and dismiss ministers (hire and fire) belongs exclusively to the prime minister. There has only been one exception to this in recent times. As part of the negotiations to form the coalition in May 2010, David Cameron had to allow the Liberal Democrats five of the 22 Cabinet posts. Nominations to these (and to an agreed number of junior posts) were the preserve of the Liberal Democrat leader and Deputy Prime Minister, Nick Clegg. When a Liberal Democrat minister resigned, Clegg found a replacement from his own party. This meant that there was a formal constraint on the prime minister's power of appointment. However, even in a single-party government a prime minister does not in practice have total freedom to appoint whom he or she wants. In practice the composition of a Cabinet will depend on a range of considerations.

· Selecting the members of a cabinet is one of the key roles played by a prime minister. If they get this wrong, they will suffer difficulties ranging from poor policy making to constant threats to their own position. It may seem simple — to choose the best men and women for the job; but there is more to it than that.

To pack the cabinet with the prime minister’s own allies. This ensures unity and bolsters the prime minister’s power, but it may lack critical voices who can improve decision making. After 1982 this was the tactic adopted by Margaret Thatcher (1979–90), an especially dominant prime minister with a great singularity of purpose. Tony Blair (1997–2007) adopted a similar approach.

To pick a balanced cabinet that reflects the different policy tendencies in the ruling party. When Theresa May became prime minister in 2016 she chose such a cabinet, which included some of her former adversaries such as Boris Johnson, David Davis, Andrea Leadsom and Liam Fox. It was especially important for her to include members who were both in favour of and against leaving the EU. She did, though, keep some key allies close to her, including Chancellor Philip Hammond and Home Secretary Amber Rudd. John Major (1990–97) was forced into choosing a similarly varied cabinet.

To pick a cabinet of the best possible people. Such a cabinet has not been seen since the 1960s and 1970s when Harold Wilson (1964–70, 1974–76) and James Callaghan (1976–79) assembled a group ‘of all the talents’. Prime ministers have complete patronage powers so they can reshuffle their cabinets at will. Some prime ministers have changed the personnel in this way annually. Dismissing and appointing new ministers is a device prime ministers can use for asserting and re-asserting their authority, as well as ensuring the quality of government.

Neutralise a potential rebel or rival — because of collective responsibility, including such a potential opponent can be an effective way of silencing them (2016 Boris Johnson) (2017 Michael Gove's return to the Cabinet as Environment Secretary after May's disastrous election- seen as an effort to neutralize a rival and placate the brexiteers)

Rewarding loyalty and including key allies — but also conciliating potential rivals Blair began his second term in 2001 by appointing several committed supporters of the New Labour project to key positions, including David Blunkett as Home Secretary and Alan Milburn as Health Secretary. They were also personally loyal to him. It is politically wise to occupy potentially troublesome MPs with senior posts, even if this means handling tensions within the team. Blair's appointment of Brown as chancellor, and his acceptance that he could not move him to another post against his wishes, is a good example of this limitation on a prime minister's freedom of action.

· Meeting expectations of diversity When he formed his first Cabinet in 1990, John Major faced adverse comment for including no women — something that he later corrected. Since then it has become the norm for prime ministers to appoint a number of female ministers, and not only to middle- and lower-ranking Cabinet posts. Margaret Beckett, made Foreign Secretary by Tony Blair in 2006, was the first woman to hold one of the three most senior posts under the prime minister. There has also been greater representation of ethnic-minority groups in recent years. Sajid Javid, a leading MP of Asian background, has served in both the Cameron and May governments.