Pairing is a long-standing informal arrangement in which an MP from one party agrees with an MP from an opposing party not to vote in a particular division (a formal vote). This allows both MPs to be absent from Westminster without affecting the final result, as their absences cancel each other out.

The system is based entirely on trust and is not a formal parliamentary rule. It is organised behind the scenes by the whips (party managers).

While informal, pairing is considered essential for the practical running of parliament, giving MPs flexibility to attend to constituency duties, ministerial business or personal matters without neglecting their party’s position in a vote.

How pairing works

Pairing is almost always arranged by the whips’ offices of the respective parties. An MP who requires a short-term absence from parliament will apply to their party’s whips. The whips will then negotiate with their counterparts in an opposing party to find an MP who also wishes to be absent for the same vote.

As pairing is an informal “gentlemen’s agreement”, it is not officially recorded in Hansard (the official report of parliament) and cannot be enforced by the speaker. Its smooth functioning relies on the trust and co-operation between the party whips.

The system would cease to operate if that trust broke down.

The pairing system can come under pressure in “hung parliaments” where a government does not have a reliable majority.

Pairing is not possible for “conscience votes” where there is no whipping operation in place.

2018 pairing controversy

In a division on 17 July 2018, a minister did not follow a pairing arrangement with an opposition MP on maternity leave.

Following the 2017 general election, the Conservative government led by Theresa May lost its majority, leading to the formation of a confidence and supply agreement with the Democratic Unionist Party (DUP).

The 2018 pairing controversy concerned a series of votes on the Trade Bill, a piece of Brexit-related legislation.

On the day of the votes, the Liberal Democrat deputy leader, Jo Swinson, was absent from Westminster as she was on maternity leave. To ensure her absence did not affect the result, she had been granted a formal pair by the Conservative Whips’ Office. Her designated pair was the then-Conservative Party chairman and minister without portfolio, Brandon Lewis.

Lewis broke the pairing agreement by voting in two crucial divisions on the Trade Bill, one on remaining in the customs union post-Brexit, which the government won by just six votes, and another on medicine regulation, which it lost.

In a post to Twitter (now X), Swinson stated: “Just how low will your govt stoop Theresa May. When [leader of the House] Andrea Leadsom delayed proxy voting motions, she assured those of us who were pregnant that we would be paired when necessary. Today your [government broke that agreement”.

Lewis responded: “I’m sorry Jo. I think it was an honest mistake made by the whips in fast-moving circumstances. I know how important the pair is to everyone, especially new parents, and I apologise.”

Labour responded by calling for the Conservative chief whip, Julian Smith, and Lewis to resign.

Leadsom was subsequently hauled before the House on 18 July to respond to an urgent question.

She told MPs: “I want to start by saying that the situation that arose yesterday, where the pair between [Swinson] and [Lewis] was broken, was not good enough. I am very sorry that it happened.

“I am assured by the chief whip that the breaking of the pair yesterday was done entirely in error and will not be repeated.”

May subsequently defended Smith, saying her chief whip had made an “honest mistake”.

May stated: “There was an honest mistake made for which the chief whip and indeed Brandon Lewis have both apologized to the member concerned.”

The development of proxy voting

The incident spurred a cross-party campaign for reform of voting procedures in the House of Commons.

On 29 January 2019, MPs agreed a proxy voting scheme for MPs who are new parents without a division. During the debate, Swinson said that proxy voting was a chance to secure a “genuinely modern parliament.”

The new system, allowing MPs on parental leave to have their vote cast by a nominated colleague, initially operated as a pilot scheme for 12 months, subject to a review by the procedure committee.

The decision was subsequently taken to make the arrangements permanent.

In June 2022, a procedure committee report found widespread support for including serious long-term injury or illness within the scheme.

On 12 October 2022, the House agreed to changes that MPs “experiencing serious long-term illness or injury should be entitled, but not required, to discharge their responsibilities to vote in this House by proxy.”

In its response to a further review by the procedure committee, the government supported “extending eligibility for a proxy vote to include serious long-term illness or injury on an ongoing basis”.

On 13 May 2024, the House agreed that an MP barred from the parliamentary estate under the risk-based exclusion policy could apply for a proxy vote.

Pairing still fills the gaps not covered by the proxy voting scheme.

An addendum to the standing orders, issued in May 2025, specified that proxy voting covers:

• childbirth;
• are of an infant or newly adopted child;
• complications related to childbirth or pregnancy, miscarriage, baby loss or extended absence for fertility treatment;
• serious long-term illness or injury;
• risk-based exclusion from the parliamentary estate

Previous pairing controversies

1979 confidence vote

The pairing system was implicated in the debate that secured the collapse of James Callaghan’s minority Labour administration. On 28 March 1979, the Callaghan government was defeated by a single vote in a motion of no confidence.

Callaghan’s administration had been clinging to power since losing its majority in 1977, initially relying on a pact with the Liberal Party.

The government’s fate was effectively sealed when the 77-year-old Labour MP Sir Alfred Broughton, bedridden after a heart attack, was warned he might not survive the journey to Westminster.

Initially, the government deputy chief whip, Walter Harrison, approached his opposite number, Conservative whip Bernard Weatherill, to secure a ‘pairing’ agreement for Broughton. Such an arrangement would have nullified Broughton’s absence, on account of a voluntary absence from a Conservative MP. Weatherill rejected any suggestion that a Tory MP would agree to a ‘pairing’ on such an important vote. But he acquiesced, honourably agreeing to abstain himself. Harrison said he would not hold Weatherill to this deal — a political sacrifice which would surely have ended his career.

The demise of Callaghan’s government was gentlemanly, at least. Weatherill would go on to serve as commons speaker from 1983 to 1992.

1976 mace seizure

On 27 May 1976, the shadow industry secretary, Michael Heseltine, seized the ceremonial Mace in the House of Commons and brandished it towards the government benches.

The protest came at the climax of a chaotic debate on a government bill to nationalise large parts of the aircraft and shipbuilding industries, which featured a pairing controversy.

A motion to effectively overturn a ruling by the speaker that the proposed legislation was a ‘hybrid bill’ (which would have subjected it to more complex standing orders) was passed by 304 votes to 303.

This came, it was alleged, after a Labour MP broke his ‘pair’. A ‘paired’ MP is a parliamentarian that has voluntarily promised not to vote – in an agreement between government and opposition whips via the ‘usual channels’. The pairing enables another MP from a separate party to be absent, usually on account of illness, without impacting the outcome of a vote. Their effective abstention is cancelled out.

In the case of 27 May 1976, had the Labour MP not broken his ‘pairing’ agreement, convention would have compelled the speaker to defeat the motion with his casting vote. ‘Speaker Denison’s rule’ says the chair should not create a parliamentary majority where one does not exist.

Heseltine seized the ceremonial mace in protest.

Meanwhile, the Conservative chief whip, Humphrey Atkins, issued a statement expressing his party’s fury over the government’s behaviour.

Atkins said: “The government won the second division by deliberately breaking a pair. It was a deliberate device by the government, and we are to end all pairing for the remainder of this session, including the prime minister.”

The Conservative opposition then boycotted all procedural cooperation with the government, including pairing, for the next month. This was a significant move, given the government did not have an overall majority. It risked the absences of MPs effectively dictating the outcome of votes.

On 22 June, Callaghan issued a statement saying the vote of 27 May would be “considered again”.

The prime minister acknowledged the allegation that the government had won the vote by “questionable means” and admitted that a “misunderstanding” had occurred with regard to pairing.

In a July 2018 interview with the BBC, Heseltine said he seized the mace because he was “appalled” by the parliamentary chicanery on the government benches.

He said: “I picked up the mace, offered it to the Labour benches and said, ‘You have abused the authority of the House, you better have the symbol as well’. And then I put it down again.”

Heseltine maintained that the pairing system “relies on trust, my word is my bond… and if you can’t believe that, then the pairing system collapses and the business of parliament becomes chaotic”.

Additional resources

• UK Parliament – House of Commons implements proxy voting pilot system for new parents: https://www.parliament.uk/business/news/2019/parliamentary-news-2019/the-house-of-commons-makes-proxy-voting-decision/