Erskine May states that the party that has the right to be called the Official Opposition is “the largest minority party which is prepared, in the event of the resignation of the Government, to assume office.”[1]

The Ministerial and other Salaries Act 1975 sets out the definition of the Leader of the Opposition: he or she is “in relation to either House of Parliament, that Member of that House who is for the time being the Leader in that House of the party in opposition to Her [sic] Majesty’s Government having the greatest numerical strength in the House of Commons.”[2]

In the event that it is unclear which is the largest minority party or who the leader of that party is, the Act states:

“If any doubt arises as to which is or was at any material time the party in opposition to Her [sic] Majesty’s Government having the greatest numerical strength in the House of Commons, or as to who is or was at any material time the leader in that House of such a party, the question shall be decided for the purposes of this Act by the Speaker of the House of Commons, and his decision, certified in writing under his hand, shall be final and conclusive.[3]

Exceptionally, if two parties were to secure the same number of seats in the House of Commons it would therefore be for the Speaker of the House to decide which of them should be accorded the status of the Official Opposition. After the number of seats won, the criterion relied on by the Speaker in reaching a determination, would most likely be each party’s share of the vote.

In a period of considerable political and electoral volatility it cannot be ruled out that the party accorded the status of Official Opposition might change during the course of the Parliament owing to deaths in office, defections, mergers, resignations or suspensions. In the event of a material change in the number of seats held by the opposition parties mid-Parliament, it would be for the Speaker to decide whether the rights and responsibilities of the Official Opposition should be transferred to another party. His decision would be guided by the statutory and parliamentary definitions of the term Official Opposition.

Nor can it be ruled out that the identity of the second-largest party in the Commons might also change during the course of the Parliament. However, the parliamentary definition in Standing Orders of the second-largest opposition party for the purpose of allocating Opposition Days explicitly states that it is the non-government party which “has the second largest number of members elected to the House as members of that party” (our italics for emphasis). As such a party which had more seats than any other opposition party other than the Official Opposition as a result of defections or a merger, would not secure the rights of the second party of opposition because its new MPs would not have been elected to the House as members of that party. There is precedent for such a scenario: when the Liberal Party and the Social Democratic Party merged in 1988 to form a new party - the Social and Liberal Democrats - they were the second largest opposition party in the House in terms of size, but the new party lost the entitlement to three Opposition Days previously held by the Liberal Party to the smaller Ulster Unionist Party.[4]

If the election result is particularly distorted, and especially if the opposition parties can muster little more than 150 seats between them, then it may be to their mutual advantage, liaising with the Speaker, to re-think the concept of how opposition is organised and resourced in a more collaborative direction.

The status of the Official Opposition and the role of Leader of the Opposition entail significant constitutional rights and responsibilities.

1. Question Time: At Prime Minister’s Question’s, the Leader of the Opposition may ask the Prime Minister up to six questions. In contrast, the leader of the second largest opposition party is usually only called upon to ask two questions. At departmental questions Opposition party spokespersons are usually permitted to ask a certain number of supplementary questions. Erskine May indicates that “members of the Shadow Cabinet and other Official Opposition spokespersons are also given some precedence in asking questions and in debate."[5]

2. Opposition Days: Under Standing Order No. 14(2), 20 days are allotted in each Session for debates on motions selected by opposition parties. Seventeen Opposition Days are at the disposal of the Official Opposition, while just three are awarded to the second largest opposition party.[6]

3. Amendments: Amendments to motions and bills tabled by the Official Opposition, and particularly by the Leader of the Opposition, are given priority in the selection of amendments by the Speaker.

4. Select Committees: While Standing Orders require the allocation of Select Committee chairs to reflect the party balance in the House, the chairs of both the Public Accounts Committee and the Standards Committee are reserved for MPs from the Official Opposition.

5. No-confidence motions: Any MP is entitled to table a motion of no confidence in the Government. However, if the Leader of the Opposition tables such a motion, then by convention the Government will make time available for that motion to be debated promptly. It is under no obligation to make such time available for any other party leader or individual MP.

6. Speech time limits: Under Standing Order No. 47, the Speaker can impose a time limit on backbench speeches.[7] That time limit does not apply to speeches made by Ministers, Shadow Ministers, or by “not more than one Member” representing the leader of the second largest opposition party.

The Speaker has also indicated that when Ministers make a Statement to the House, he expects their speech to take no longer than 10 minutes, with a similar expectation of five minutes for the Shadow Minister, and just two minutes for the spokesperson from the third party.[8] A similar convention applies to Urgent Questions (UQs), with a three-minute limit for the Minister’s response to the UQ, two minutes for the Shadow Minister, and one minute for the third-party spokesperson.

7. Short Money: Since 1975 opposition parties have received funding to support their parliamentary activities. The funding is available to all opposition parties that win either two seats, or one seat and more than 150,000 votes in the most recent General Election.

The funding has three components:

1. General funding to support parliamentary business;

2. Travel expenses; and

3. Funding for the Leader of the Opposition’s office.

Parties largely use the general funds to provide research and policy support to their frontbench and to fund staff in the Whips’ and Leader of the Opposition's offices.

In 2023-24, the parties received £21,438.33 in Short Money for every seat they won in the most recent General Election, plus £42.82 for every 200 votes the party received.

A total of £235,511.46 to cover travel expenses is also divided proportionately among the parties in accordance with the same formula.

In addition to the general funding and travel expenses, a sum of £998,817.35 was made available to cover the costs of running the Leader of the Opposition’s Office.[9]

The per seat and per vote general funding, the travel expenses, and the funding for the Leader of the Opposition’s Office have since been uprated for 2024-25 in line with the Consumer Price Index in December 2023 (which was 4.0% according to the Office for National Statistics).[10]

[1] Erskine May’s treatise on the law, privileges, proceedings and usage of Parliament, 25th edition, 2019, para. 4.6

[2] Ministerial and other Salaries Act 1975, section 2(1)

[3] Ministerial and other Salaries Act 1975, section 2(2)

[4] Erskine May’s treatise on the law, privileges, proceedings and usage of Parliament, 25th edition, 2019, para. 18.13

[5] Erskine May’s treatise on the law, privileges, proceedings and usage of Parliament, 25th edition, 2019, para. 4.6

[6] Standing Order No.14(2), House of Commons Standing Orders for Public Business, as at 23 October 2023

[7] Standing Order No.47, House of Commons Standing Orders for Public Business, as at 23 October 2023

[8] House of Commons, Hansard, 18 May 2016, vol. 611, col. 1

[9] Kelly, R. (8 June 2023), House of Commons Library, Short Money

[10] Office for National Statistics, Consumer price inflation, UK: December 2023