A confidence and supply agreement is a political arrangement that can enable a party without a majority of seats in a legislature to form a stable minority government. It is a formal deal in which a smaller party or independent members agree to support the government in key parliamentary votes.

These agreements are a means by which a minority administration in a “hung parliament” can pass legislation, doing so with the support of a smaller party. They are less formal than a full coalition government, where the junior party takes ministerial posts.

The two core elements of any such deal are ‘supply’ and ‘confidence’. The smaller party agrees to back the government in votes on these two matters, ensuring the government can function and survive in office.

What is a confidence and supply agreement

Confidence

The “confidence” in a confidence and supply agreement refers to the government’s ability to command the confidence of the House of Commons. The supporting party pledges to vote with the government on any formal motion of no confidence, or to abstain from such a vote.

If a government loses a vote of confidence, it is expected to resign or seek a general election.

Supply

The “supply” in a confidence and supply agreement refers to the government’s ability to raise money and spend it. The non-governmental signatory to a confidence and supply agreement states their willingness to vote with the government on the budget and other “supply bills”.

The refusal of supply resulting from the defeat of a supply bill can be fatal for a government, meaning it cannot fund public services or sustainably carry out its policies.

How a confidence and supply agreement differs from a coalition

In a coalition, the smaller party joins the government and its senior members take up ministerial posts in the cabinet. For instance, in the Conservative-Liberal Democrat coalition government (2010-2015), Nick Clegg held office as deputy prime minister.

In a supply and confidence deal, the supporting party remains outside of government and does not assume ministerial office.

In a coalition, all ministers are bound by the principle of collective responsibility, and thereby are required to support the government on all issues. Both majority and minority parties in a coalition take the same whip (provided there is no “agreement to differ” on a specific issue).

In a supply and confidence deal, the supporting party is only bound on the specific issues of supply and confidence. On all other legislation, it is free to vote against the government.

The Conservative-DUP confidence and supply agreement

The general election held on 8 June 2017 resulted in a hung parliament, a shock outcome that saw the Conservative Party lose its parliamentary majority.

The prime minister, Theresa May, called the snap election on 18 April 2017, despite previous insistences she would not, with a view to capitalising on the Conservative Party’s large poll lead (as high as 20 points) over Labour.

The result left the Conservatives as the largest party with 317 seats, a net loss of 13 and nine short of the 326 required for an overall majority. Labour made a net gain of 30 seats to finish on 262.

To remain in power, May entered into negotiations with the Democratic Unionist Party (DUP).

After a period of negotiations from 9 June to 26 June, a formal agreement was signed in Downing Street by the Conservative chief whip, Gavin Williamson, and the DUP’s chief whip, Sir Jeffrey Donaldson, in the presence of the two party leaders, Theresa May and Arlene Foster.

The DUP had already supported the first queen’s speech of the new parliament on 21 June.

Under the terms of the confidence and supply deal, the DUP agreed to support the government on all motions of confidence and on all supply bills, including the budget and other financial legislation. It also committed to providing support to legislation pertaining to national security and the UK’s exit from the European Union.

May’s government also agreed to maintain the ‘triple lock’ on pensions and universal winter fuel payments – policies which had been included, policies which had been dropped from the Conservative 2017 election manifesto.

In return, the government pledged an additional £1 billion of funding for Northern Ireland over two years, to be spent on infrastructure, health, and education. The DUP also secured the statement that the Conservative Party will “never be neutral in expressing its support” for the Union.

In a statement, May said: “I welcome this agreement which will enable us to work together in the interest of the whole United Kingdom, give us the certainty we require as we embark on our departure from the European Union, and help us build a stronger and fairer society at home. In the interests of transparency, the full terms of this agreement have been published.”

The DUP leader, Arlene Foster said she was “delighted” with the package.

She commented: “We’re delighted that we have reached this agreement, which I think works, obviously, for national stability.”

The deal provided May with a narrow working majority, allowing her to remain in office, but it left her government constantly vulnerable to pressure from the DUP and eurosceptic voices on her backbenches, notably the European Research Group (ERG).

The DUP did not support the prime minister’s withdrawal agreement in any of the three so-called ‘meaningful votes’ held from January to March 2019. Opposition to May’s Brexit deal centred on the Northern Ireland backstop – the agreement’s proposed solution to the Irish border problem. The mechanism, designed to maintain an open border on the island of Ireland in any Brexit scenario, provided for a UK-wide customs union with the EU, covering all goods (except for fish). The backstop would apply indefinitely, until the UK and EU agreed on a different arrangement.

The DUP did support May’s government in the vote of confidence that followed the first meaningful vote on 16 January 2019. The government won that vote by 325 to 306, a majority of 19.

Nigel Dodds, the leader of the DUP in the commons, spoke during the 16 January debate. “Following the general election, we entered into the confidence and supply agreement with the Conservative party, in the national interest, to pursue the agreed objectives as set out in that agreement”, he said.

Dodds added: “Now we have this no-confidence motion before us. We believe it is in the national interest to support the government at this time so that the aims and objectives of the confidence and supply agreement we entered into can be achieved.

“Much work remains to be done on those matters.”

The DUP-Conservative confidence and supply agreement technically remained in place until the dissolution of the parliament in November 2019.

The Conservative Party, now led by Boris Johnson as prime minister, won the December 2019 general election with a resounding 80-seat majority. There was now no longer any reason to continue the Tory-DUP pact.

The Lib-Lab pact

Shortly after entering Downing Street, Labour prime minister James Callaghan saw his parliamentary majority eroded due to a series of by-election defeats. He initially sought to remain in office through an agreement known as the “Lib-Lab Pact”.

A joint statement announcing the Lib-Lab pact was issued 23 March 1977. It confirmed the creation of a joint consultative committee, established under the leader of the House, Michael Foot, to examine policy before it reached the floor of the House.

Under the terms of the pact, Callaghan pledged to progress legislation for Scottish and Welsh devolution – a key Liberal demand.

The statement added: “We agree that this arrangement between us should last until the end of the present parliamentary session, when both parties would consider whether the experiment has been of sufficient benefit to the country to be continued.”

The government also committed to subject forthcoming legislation concerning elections to the European parliament to a free vote. The European Assembly Elections Bill included a procedural device that allowed the proposed first past the post system and proposed PR system to be set out in the same bill. This would leave the choice of determining the electoral system to a free vote of MPs during the bill’s committee stage. An anti-PR amendment was ultimately approved by 319 votes to 222.

The pact ended in the summer of 1978, after 15 months, depriving the government of 13 crucial parliamentary votes. It came as Callaghan ruled out the possibility of an autumn election. Labour was left to rely on ad-hoc support and an often innovative whipping operation.

On 28 March 1979, the Labour government was defeated by a single vote in a motion of no confidence. The successful no-confidence motion – passed by 311 votes to 310 – led directly to the 1979 general election. Liberal MPs, led by David Steel, voted against the government.

Confidence and supply agreement in the devolved nations

Agreements between parties to support a minority government are a more common feature of politics in the devolved legislatures.

Scotland

From August 2021 to April 2024, the Scottish National Party (SNP) governed with the support of the Scottish Green Party through a power-sharing deal known as the Bute House Agreement. The agreement followed the May 2021 Scottish parliament election, in which the SNP won 64 of the 129 seats, one short of an overall majority.

Two Green MSPs, Patrick Harvie and Lorna Slater, were appointed as ministers. Under the deal, Green ministers attended cabinet meetings at least twice a year.

The deal was in many ways more similar to a formal coalition. Nonetheless, the SNP and Greens agreed several prominent exceptions to the principle of collective responsibility. The pact was referred to as a “cooperation agreement”.

Referring to the Greens in government, the agreement stated: “These ministers will, as a consequence of the agreed processes for cooperation and collaboration as set out in co-operation and collaboration, observe the principle of collective responsibility, except in respect of excluded matters.”

The SNP ended the agreement in April 2024, choosing to govern as a minority administration. This led to the downfall of Humza Yousaf as first minister.

Wales

From December 2021 until May 2024, the Welsh Labour government operated with support from Plaid Cymru through a formal “co-operation agreement”.

This was not a formal coalition, but a deal to collaborate on a total of 46 policy areas. Plaid instead appointed special advisers to serve in the offices of the Welsh government.

Adam Price, the leader of Plaid, said his party was “transforming itself from a traditional opposition party in the Westminster sense to something new and refreshingly different, a co-opposition party, co-operating where possible, while continuing to oppose, and to scrutinise and criticise where necessary”.

In May 2024, Plaid Cymru withdrew from the agreement. The party’s latest leader, Rhun ap Iorwerth said the decision was related to controversies surrounding the new first minister, Vaughan Gething, and what he called “a significant lack of judgement.”

Northern Ireland: The Northern Ireland executive and assembly operate under a mandatory power-sharing system required by the Good Friday Agreement (GFA).

Additional resources

• Institute for Government: https://www.instituteforgovernment.org.uk/
• Text of the 2017 Conservative-DUP Agreement: https://www.gov.uk/government/publications/conservative-and-dup-agreement-and-uk-government-financial-support-for-northern-ireland
• House of Commons Library – Confidence and Supply: Northern Ireland’s £1 billion: https://commonslibrary.parliament.uk/confidence-and-supply-northern-irelands-1-billion/