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What is a party whip?

Keeping MPs voting together · 2 min read
Part of: Parties and politicians · 8 short reads
This is number 6 of 8

The nutshell

A party whip is an MP whose job is to keep a party's MPs voting together. The word whip also means the weekly note that tells MPs how important each vote is.

Every fact on this page comes from official rules and non-partisan explainers. Each source tag — like Parl — opens where a fact comes from.

Keep scrolling. The basics is next

The basics

What a whip is

In Parliament the word whip has two meanings. A whip is an MP appointed by a party to help organise its MPs, most of all when there is a vote.ParlThe Institute for Government says whips work to make sure a party's members vote in line with the party leaders.IfG

The Whip — the weekly note

The word whip is also the name of a note. Each week the whips send round a written note, called The Whip, that lists the votes coming up.ParlEach vote is underlined to show how much it matters. A vote underlined three times is a three-line whip, which the party treats as essential.Parl

When an MP votes against the whip

A whip is an instruction from a party, not a law.IfGAn MP who breaks a three-line whip can have the whip removed. That MP then sits as an Independent, while keeping the seat, according to UK Parliament.Parl

When no whip applies

Whips do not decide every vote. On some questions no whip is applied, and each MP votes freely — a free vote. The House of Commons Library has kept a list of free votes in the House of Commons since 1979.HoC

What supporters say
  • The Institute for Government notes that whips help a party's MPs act together, so a government with a majority can usually pass its plans
  • UK Parliament says a weekly note called The Whip tells MPs in advance which votes matter most
  • On some questions no whip is applied and MPs vote freely, and the House of Commons Library has listed these free votes since 1979
What critics say
  • The Institute for Government describes a three-line whip as an instruction, not a law, so an MP can still vote against it
  • An MP who breaks a three-line whip can have the whip removed and then sit as an Independent, according to UK Parliament
  • A whip is both a party official and the party's written note, so the same word means two things, which is a common mix-up
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1. In UK politics, what is a party whip?
2. What does a three-line whip mean?
3. What can happen to an MP who defies a strict whip?
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The deep end6 min

What whips are, and what whips do

Whips are MPs, and in the House of Lords peers, appointed by each party to help organise its part in the work of Parliament, according to the House of Commons Library.HoC The Institute for Government describes the main aim as making sure a party's members vote in line with the party leadership.IfG Whips also arrange much of the timetable of business between the parties.HoC

The Whip, and the three lines

Each week the whips send members a written note, also called The Whip. It sets out the business coming up, and marks each vote, or division, by underlining.Parl A vote underlined once is routine. A vote underlined three times is a three-line whip, which UK Parliament describes as essential, and is used for major moments such as the second reading of an important Bill.Parl

Losing the whip

A whip is an instruction from a party, not a rule of law, as the Institute for Government sets out.IfG An MP who defies a strict whip can have the whip withdrawn. UK Parliament explains that the MP is then, in effect, outside the party and sits as an Independent, but keeps the seat until the whip is restored.Parl

Free votes

Not every vote is whipped. On some questions, often matters of conscience, no whip is applied and each MP votes as that MP chooses. This is called a free vote. The House of Commons Library has recorded free votes in the House of Commons since 1979.HoC

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Last updated 12 July 2026 · next review January 2027
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