The Prime Minister and the Cabinet

No Act of Parliament creates the office of Prime Minister, sets its powers or defines its duties. The role grew by convention out of the Crown's need for a chief minister, and its formal authority is borrowed: the royal prerogative supplies the powers, and convention supplies the rules for using them.

That produces an office whose strength varies enormously with circumstances. Six resources make up a Prime Minister's power base:

Resource	What it delivers	Where it can fail
Party leadership	Command of the governing party and its whips	Party rules allow leaders to be challenged and removed
Patronage	Appointing, promoting and sacking ministers, peers and senior officials	Sacked ministers become dangerous backbenchers
Prerogative powers	Military deployment, treaties, machinery of government	Constrained by statute, the courts and convention
Control of the Cabinet	Setting the agenda, summing up discussion, appointing committees	Cabinet can withdraw its support collectively
A Commons majority	Getting a legislative programme through	Shrinks with rebellions, by-elections and defections
Public standing	Authority over colleagues who want to keep their seats	Poll ratings can collapse inside a single year

A Prime Minister is powerful because of their party, not independently of it. Every case study in this content area is ultimately a story about that dependence.

Formally the Prime Minister's power of appointment is close to unlimited. In practice five pressures compete, and a Cabinet is the compromise between them.

Factor	What it pushes towards	Illustration
Establishing authority	Loyalists in the posts that matter	Boris Johnson's 2019 Cabinet was built around committed supporters of leaving the EU
Containing rivals	Giving beaten opponents office so they are bound by collective responsibility	John Major gave Douglas Hurd and Michael Heseltine senior posts in 1990 after defeating both
Ability and experience	Competence in the great offices of state	Departments such as the Treasury and Home Office punish inexperience quickly
Balance between factions	Representing each wing of the party	Ignoring a faction leaves an organised bloc on the backbenches
Representation	Gender, ethnic and regional breadth in a visible Cabinet	Cabinets are photographed and compared with the country

Two hard limits sit underneath all five. The House of Commons Disqualification Act 1975 allows a maximum of 95 ministers to sit and vote in the Commons, and enough ministers must sit in the House of Lords to answer for departments there.

Worked example — forming a government in July 2026. Andy Burnham took office in unusually constrained circumstances, and every factor above was in play.

1. No electoral mandate of his own. He became Prime Minister on 20 July 2026 without a general election, having entered the Commons at the Makerfield by-election on 18 June 2026.
2. An unusually strong party mandate. He was elected Labour leader unopposed on 17 July 2026 with 379 MP nominations — over 94% of the parliamentary party — which is far more internal backing than a contested contest would have produced.
3. A fractured party to bind in. A Financial Times analysis in November 2025 identified five distinct Labour factions manoeuvring against Sir Keir Starmer, including Blairites, the socialist left and the soft left in which Burnham himself sat. Around 103 Labour MPs had called for Starmer to go.
4. Almost no personal Commons network. A Prime Minister who has been an MP for a month cannot draw on years of shared committee work and whips' office favours when judging who is competent and who is loyal.

The tension is the exam point: overwhelming party authority combined with an unusually thin personal and electoral base. Which of those matters more is a genuine judgement question.

Comparing formations shows that the same power is used to solve different problems.

	Thatcher, 1979	Blair, 1997	Johnson, 2019
Starting position	Won a majority of 43, but led a party whose senior figures did not share her economics	Won a majority of 179 with a party recently transformed	Took over a minority government committed to leaving the EU
Strategy	Appoint the party's senior "wets" despite disagreeing with them, hold the key economic posts, replace the rest later	Concentrate power in a small group; grant the Chancellor unusual autonomy	Appoint on a single test — support for delivering Brexit
Key appointment	Geoffrey Howe at the Treasury, to drive monetarist policy	Gordon Brown as Chancellor, with wide control of domestic policy	Dominic Raab as Foreign Secretary and effective deputy
Rivals	Left in post initially, then removed	John Prescott, beaten for the leadership, arrived with a deputy leadership won in his own right; Blair bound him in with the deputy premiership and a large department	Jeremy Hunt, the defeated leadership rival, was offered Defence and refused it
Turning point	The September 1981 reshuffle removed Ian Gilmour, Christopher Soames and Mark Carlisle and promoted Norman Tebbit, Nigel Lawson and Cecil Parkinson	Brown's grip on the Treasury became a rival power centre Blair could not dislodge	Sajid Javid was replaced as Chancellor by Rishi Sunak in February 2020 after refusing to merge his advisers with Number 10's

The 1981 reshuffle is the sharpest single illustration of patronage as a weapon: a Prime Minister who had been in a minority in her own Cabinet on economic policy in 1979 had rebuilt it into a supportive one within two years, without an election intervening.

The same office produced Blair's ascendancy in 1997 and Theresa May's paralysis in 2019. Five variables account for most of the difference.

1. The size of the Commons majority

A large majority absorbs rebellions. In January 2019 Theresa May, governing without a majority on a confidence-and-supply agreement with the DUP, lost the vote on her Brexit deal by 432 votes to 202 — the heaviest government defeat in modern Commons history. The 2024 general election, by contrast, returned Labour with a majority of 174, and it was that Parliament Andy Burnham inherited when he became Prime Minister in July 2026 — a starting position nothing like May's.

2. Unity within the governing party

Divisions turn every decision into a negotiation. Party management consumed John Major's premiership after 1992 and Theresa May's after 2017.

3. Personal popularity and poll standing

Ministers defer to a leader who wins elections and stop deferring when the leader looks like a liability. Polling as of early September 2026 illustrates how thin that cushion can be: YouGov's poll of 6–7 September 2026 put Labour on 23%, Reform UK on 23%, the Conservatives on 20%, the Greens on 12% and the Liberal Democrats on 11–12%.

4. Events

Crises concentrate authority on whoever leads the response — and then hand out the blame. The Falklands conflict rebuilt Margaret Thatcher's standing in 1982; the coronavirus pandemic gave Boris Johnson exceptional freedom in 2020 and, through the Partygate revelations, helped end his premiership in 2022.

5. Time in office

Authority decays. Sacked ministers accumulate on the backbenches, manifesto commitments run out, and MPs begin thinking about the next leader. There is no recent example of a Prime Minister who was stronger in their final year than their first.

Full Cabinet is a body of around twenty senior ministers meeting for a limited time each week. Detailed policy is settled elsewhere, and the Prime Minister controls where.

• Cabinet committees. A committee decision carries the authority of the full Cabinet. The Prime Minister decides which committees exist, what they cover and who chairs them. Government material dated October 2021 showed roughly twenty committees and sub-committees, of which Boris Johnson chaired eleven, with allies taking most of the rest.
• Small inner groups. Johnson set up a "Brexit war cabinet" of six ministers in 2019. During the pandemic, reporting indicated key decisions were taken by an inner core of four — Johnson, Rishi Sunak, Michael Gove and Matt Hancock — while full Cabinet met over video links and largely ratified decisions already taken in the Covid sub-committees.
• Bilaterals. A one-to-one meeting between the Prime Minister and a departmental minister settles a policy before colleagues see it. Cabinet then receives a decision rather than a choice.
• Number 10 and the Cabinet Office. The Prime Minister's Office, the Policy Unit created in 1974, and the Cabinet Office give the centre analytical capacity that individual departments must negotiate with.
• Special advisers. Political appointees who work for ministers but can be directed from the centre. Dominic Cummings was given authority over all government special advisers in 2019 and demonstrated it in August 2019 by dismissing a Treasury adviser without the Chancellor's agreement.

Worked case study — informality and its limits. The Butler Review, published in July 2004, examined the intelligence used to justify the invasion of Iraq and criticised the informality of the government's decision-making procedures: too few papers, too little collective consideration, too much settled in small unminuted meetings. The label "sofa government" stuck. The episode shows both sides of the argument at once — a Prime Minister can run policy outside Cabinet, and the eventual reckoning for doing so lands on the Prime Minister personally.

Examiners reward candidates who deploy a model rather than merely listing examples.

Model	Core claim	Strongest evidence	Weakness
Cabinet government	Decisions are taken collectively; the Prime Minister is chair of a committee of colleagues	Cabinet's formal authority is real: Thatcher fell in 1990 and Johnson in 2022 once colleagues withdrew support	Most decisions are settled before Cabinet meets
Prime ministerial / presidential government	One person dominates: patronage, media focus, a personal staff and direct public appeal	Richard Crossman argued in 1963 that Cabinet government had already given way to prime ministerial government; Michael Foley later described a "British presidency"	A Prime Minister has no separate electoral mandate and can be removed by their party at any time
Core executive	Power is a network of dependencies; each actor holds resources the others need and must trade them	Blair could not remove Brown, because the Treasury held resources he needed; coalition government in 2010–15 was openly transactional	Harder to write about crisply than a simple PM-versus-Cabinet contest

The core executive model is the strongest analytical tool here, because it explains variation. A Prime Minister with a large majority, a united party and good polling holds most of the resources; the same office holder two years later may hold very few.

Build both sides before judging.

Evidence that prime ministerial power has grown:

• An expanded Number 10 and the Policy Unit created in 1974, working alongside the Cabinet Office, give the centre an analytical capacity it did not have before the 1970s.
• Elections are fought around leaders and televised debates, personalising the mandate.
• Policy is routinely settled in committees, bilaterals and inner groups, with Cabinet ratifying.
• Prerogative powers such as military deployment and machinery-of-government changes sit with the Prime Minister personally.

Evidence that the Cabinet and the party remain decisive:

• Cabinet withdrawal of support ended Margaret Thatcher's premiership in November 1990 and Boris Johnson's in July 2022.
• A powerful Chancellor can hold an independent base, as Gordon Brown did between 1997 and 2007.
• Coalition in 2010–15 forced formal bargaining through "the Quad" of Cameron, Osborne, Clegg and Alexander.
• Losing a majority strips the office bare: Theresa May offered to resign in March 2019 to get her deal through, and it still failed.
• In June 2026 several Cabinet ministers resigned and around 103 Labour MPs called publicly for Sir Keir Starmer to go; he announced his resignation on 22 June 2026.

A defensible judgement is that the Prime Minister's capacity has grown while their security has not. The centre commands more machinery than at any point in the twentieth century, yet four of the five Prime Ministers who left office between 2019 and 2026 — May, Johnson, Truss and Starmer — went because their own party removed them, not because voters did.

1. Treating "presidential" as a conclusion rather than a claim

The comparison has real limits: a Prime Minister sits in the legislature, depends on a party for their job, and holds no personal electoral mandate. Use the term, then test it.

2. Listing selection factors without weighing them

Section 3.3.1 names the factors governing ministerial selection. A list scores AO1; explaining why one factor dominated a particular formation — authority in 2019, party balance in 1990 — scores AO2.

3. Assuming a large majority guarantees dominance

Blair had majorities of 179 and 167 and still could not move Gordon Brown from the Treasury. Majority size is one variable among several, not the whole answer.

4. Writing about Cabinet as if it debates policy from scratch

Committees, bilaterals and inner groups usually settle matters first. The interesting question is what full Cabinet still does: legitimising decisions, binding ministers through collective responsibility, and occasionally removing a Prime Minister.

5. Using stale contemporary examples

Sir Keir Starmer ceased to be Prime Minister on 20 July 2026, when Andy Burnham took office. Attach a date to every current claim — poll figures in particular, which should carry both the pollster and the fieldwork dates.

6. Reaching no judgement

The 30-mark command word is Evaluate, with 10 marks for AO3. Decide whether capacity or security is the better measure of prime ministerial power, and argue for your choice in the conclusion rather than restating the balance.