A reference guide to UK legislative procedure for readers who don't work with it every day.
Westminster Brief — May 2026
Most laws begin as bills. A bill is a proposal for a new law, or a change to an existing one. Before it can become law, a bill must pass through both Houses of Parliament — the Commons and the Lords — and receive the formal approval of the Monarch. The full process typically takes between several months and over a year, depending on the bill's complexity and political weight.
Different types of bill follow slightly different procedures. The most common type is a government bill, introduced by a Minister, taken through both Houses, and amended along the way. Private Members' Bills, Private Bills, Hybrid Bills, and Money Bills each follow variations of the standard procedure.
This guide describes the standard journey first, then notes where procedure varies. It's structured for scanning rather than continuous reading: jump to the section you need.
Bills don't appear from nowhere. By the time a bill is formally introduced in Parliament, it has usually been through a considerable amount of preparatory work — much of which takes place outside parliamentary procedure altogether.
Green Papers and White Papers. Where a government department wants to legislate on a substantial policy area, it may first publish a Green Paper (a consultative document, open to feedback and exploration) or a White Paper (a more developed statement of intent that signals the government's preferred direction). These can precede legislation by months or, in some cases, by years. They give interested parties — sector bodies, charities, regulators, opposition parties — an opportunity to comment before a bill is drafted.
Public consultations. Most major bills are preceded by formal public consultations, in which the responsible department invites written responses on specific policy proposals. Departments are expected to publish a response to the consultation that summarises the views received and explains how they have shaped subsequent policy decisions.
Pre-legislative scrutiny. Some bills — usually the most substantial or politically sensitive — are published in draft form before being formally introduced. A relevant select committee can then examine the draft, take oral and written evidence from witnesses, and recommend changes. The government is not bound to accept these recommendations, but in practice many are adopted. Pre-legislative scrutiny is increasingly common but not standard; smaller or more time-sensitive bills usually skip it.
Who actually drafts the bill. Government bills are drafted by the Office of the Parliamentary Counsel, a small specialist office within the Cabinet Office staffed by around 50 Counsel — the specialist drafting lawyers themselves — supported by approximately 10 administrative and support staff. This is a distinct role from the legal advisers in individual departments. Departmental lawyers advise on the policy that the bill is intended to implement; Parliamentary Counsel turn that policy into the precise legal text. Most Parliamentary Counsel are barristers or solicitors who spend much of their career in the office, accumulating institutional knowledge about how UK legislation is structured and how new bills interact with existing statute.
This is unusual by international standards. Most other jurisdictions do not have a single specialist drafting office for primary legislation; legislative text is more often produced by departmental lawyers, parliamentary staff, or in some cases by lobbyists. The UK convention concentrates drafting expertise in one place and is one reason UK statutes have a particular consistency of style and structure.
How the drafting actually happens. Once a department has decided what it wants its bill to do, its policy officials prepare detailed instructions to Counsel — a document setting out the policy aim, the legal effect required, and the edge cases to handle. For complex bills these instructions can run to hundreds of pages. Parliamentary Counsel then drafts the bill, with iteration between Counsel, the department, and ministers over weeks or months. The bill is then formally cleared through Cabinet committee procedure before being introduced in Parliament.
Private Members' Bills are sometimes different. Where the government supports a Private Member's Bill, Parliamentary Counsel will often draft it on the same basis as a government bill. Where a Private Member's Bill is hostile to government policy or addresses a minority concern, the MP may need to find drafting assistance elsewhere — from a parliamentary group, a sympathetic external lawyer, a campaigning organisation, or in rarer cases from a private drafter. This explains some of the variation in drafting quality across Private Members' Bills, and why some are technically rougher than government bills even when their policy intent is sound.
By the time a bill reaches its First Reading, then, much of its content has already been shaped. The parliamentary stages that follow are where it gets debated, scrutinised, and amended — but they are not where it is invented.
This section describes the standard procedure for a public government bill introduced in the House of Commons. Bills introduced in the Lords follow the same stages in reverse order. Variations for other bill types are noted in the next section.
A purely formal stage. The bill is introduced; its title is read out; there is no debate and no vote. The bill is then published in full, along with its Explanatory Notes and (for most government bills) an accompanying Impact Assessment.
First Reading marks the bill's formal arrival in Parliament, but no scrutiny takes place. The substantive work begins at Second Reading.
The first substantive debate. Members of Parliament debate the general principles of the bill — not its specific clauses, but whether the policy direction is one the House supports. At the end of the debate there is usually a vote (a "division") on whether the bill should proceed to Committee stage.
Defeat at Second Reading is rare for government bills, because the government typically controls a majority. Where it does happen — as occasionally with Private Members' Bills, or with government bills facing significant rebellion — the bill stops here and goes no further.
For government bills with public spending implications, a separate Money Resolution must be passed in the Commons after Second Reading. Without this, the bill cannot progress to Committee. Money Resolutions are usually formality, but they are technically distinct from the Second Reading vote itself.
Where the bill is examined clause by clause. Most government bills go to a Public Bill Committee — a small committee of MPs, chosen to reflect the party balance of the Commons, who consider the bill in detail over several sittings.
Public Bill Committees typically begin with one or more sittings of oral evidence, in which witnesses appear before the committee to give views on the bill. Witnesses often include civil servants from the sponsoring department, sector experts, regulators, affected stakeholders, charities, and professional bodies. Written evidence is accepted in parallel. The evidence gathered at this stage often shapes the amendments tabled later in committee and at Report stage.
Once evidence is heard, the committee moves to detailed scrutiny: working through the bill clause by clause, with amendments proposed and debated. Government amendments are common at this stage and usually pass. Opposition amendments are usually defeated unless they have government support, but the process forces ministers to explain and defend each clause on the record.
Some bills — typically those of major constitutional significance — bypass Public Bill Committee and are instead considered by a Committee of the Whole House. In this case all MPs can participate in the clause-by-clause scrutiny on the floor of the Commons. There are no evidence sessions in this format.
Once the committee has reported the bill back to the Commons, the whole House considers it again. At Report Stage, further amendments can be proposed and voted on. This is often where the government tables substantive amendments responding to committee debate, opposition pressure, or representations received during the bill's progress so far.
Report Stage can take place over several days for major bills, with different sections of the bill grouped for separate debate.
A final debate on the bill in its current form. No further amendments to the substance are possible; only minor drafting changes can be made. The vote at Third Reading sends the bill to the Lords.
By this point the bill has been substantially shaped. Most of the politically meaningful changes will have been made at Committee or Report; Third Reading is largely a stocktake.
The bill then begins again in the House of Lords, going through First Reading, Second Reading, Committee, Report, and Third Reading in the same order. The Lords stages broadly resemble those in the Commons, with some differences:
Lords Committee Stage is usually taken on the floor of the House rather than in a small committee, and does not include oral evidence sessions of the kind seen in Public Bill Committee. Detailed amendments are debated in turn by any peer who wishes to participate.
The Lords often takes a more procedurally relaxed and substantively detailed approach to scrutiny than the Commons. Lords amendments may reflect cross-party concerns, the views of independent crossbench peers, or detailed expert input from peers with relevant professional backgrounds.
When the Lords sends the bill back to the Commons, the Commons must consider any Lords amendments. The Commons may accept them, reject them, or amend them further. If the two Houses disagree, the bill can move back and forth between them — a process informally known as "ping-pong" — until agreement is reached or, in rare cases, the Parliament Acts are used to bypass the Lords.
Most ping-pong is resolved relatively quickly through compromise or government concession. Sustained disagreement is rare and usually only occurs on bills with significant constitutional, civil liberties, or fiscal implications.
Once both Houses have agreed the bill in identical form, it receives Royal Assent — the Monarch's formal approval, given on the advice of ministers. Royal Assent is now a procedural formality and has not been refused since 1708, when Queen Anne withheld her approval from the Scottish Militia Bill amid fears that an armed Scottish militia might side with a French invasion. No monarch since has refused assent to a bill that has completed its parliamentary passage. The bill becomes an Act of Parliament and enters the statute book.
Some provisions of an Act take effect immediately on Royal Assent; others come into force on specific dates, or on dates set by subsequent commencement orders made by ministers.
The formal stages set out above describe the procedure. They do not, by themselves, describe where the substance of a bill is decided. For readers trying to understand how a bill actually evolves — and where to intervene if they want to influence it — the more useful map looks different.
Consultation responses shape the policy before it reaches Parliament at all. Once the policy is set, the bill's text follows.
Evidence to Public Bill Committee is the principal formal point at which outside expertise enters the parliamentary process. Written evidence has lower friction than oral evidence and is read by committee staff and members.
Government amendments at Report Stage are where the government most often makes concessions in response to political or sector pressure. Many of the most significant changes to bills happen here.
Lords amendments often introduce substantive changes that would have been politically difficult to make in the Commons. Where the government cannot defeat the Lords amendments in subsequent ping-pong, they may be retained.
Statutory Instruments made after Royal Assent can substantially shape how an Act operates in practice. Acts often delegate detail to secondary legislation, and the regulations made under that delegation are themselves consequential.
Understanding bills well — as a policy professional, a journalist, or an informed citizen — means following all of these, not only the formal Hansard record of the parliamentary stages.
Several types of bill follow procedures that differ from the standard one.
Private Members' Bills are introduced by MPs or peers who are not ministers. There are several routes by which they can be introduced — the Private Members' Ballot, the Ten Minute Rule, and Presentation — and the procedural prospects of each differ. In practice, the great majority of Private Members' Bills do not become law. They require parliamentary time that the government controls, and most are blocked at one stage or another. Ten Minute Rule bills in particular exist largely to put an issue onto the parliamentary record and to test cross-party support; they almost never progress to Royal Assent.
Some Private Members' Bills do become law, particularly on subjects where the government is willing to provide time or where there is cross-party consensus. Major social legislation in recent decades has occasionally come through this route.
Private Bills apply to a specific person, place, or organisation rather than to the general public. They are usually introduced by petition from the body affected — for example, by a railway company, university, or local authority seeking specific statutory powers. Private Bills follow a partly different procedure that allows affected parties to petition against them and to give evidence to a special committee.
Hybrid Bills combine elements of both public and private legislation. Where a public policy affects specific identified interests — most notably with major infrastructure projects such as HS2 — Hybrid Bill procedure is used. Affected parties can petition against the bill, and a Hybrid Bill Select Committee considers their objections in detail. This process can extend a Hybrid Bill's progress over many years.
Money Bills are bills certified by the Speaker as dealing solely with national taxation, public spending, or related financial matters. They follow an accelerated procedure: the Lords can consider them but cannot substantively amend them, and they must receive Royal Assent within one month of being sent to the Lords. The annual Finance Bill is the most familiar example.
Statutory Instruments are not bills, but they are part of the broader picture of how law is made. An Act of Parliament typically grants ministers the power to make detailed regulations under the Act; those regulations are made as Statutory Instruments. Many of the practical effects of legislation are set out in Statutory Instruments rather than in the parent Act itself.
Statutory Instruments are subject to parliamentary scrutiny but the procedure is much shorter than for bills. Most are made under the "negative resolution" procedure, which means they take effect unless Parliament objects within a set period. A smaller number require positive parliamentary approval ("affirmative resolution") before they can take effect.
Act of Parliament. A bill that has received Royal Assent and become law.
Bill. A proposal for legislation that has been introduced into Parliament but has not yet become law.
Carry-over motion. A procedural motion allowing a bill that has not completed its passage by the end of a parliamentary session to resume in the next session, rather than starting again from scratch.
Commencement order. A Statutory Instrument that brings a particular provision of an Act into force on a specified date.
Erskine May. The authoritative reference work on parliamentary procedure, formally titled Erskine May's Treatise on the Law, Privileges, Proceedings and Usage of Parliament. Updated periodically.
Explanatory Notes. A document accompanying a bill that explains, in plain English, what each clause is intended to do. Drafted by the sponsoring department, not by Parliament.
Hansard. The official report of the proceedings of both Houses of Parliament.
Impact Assessment. A formal document accompanying most government bills, setting out expected costs, benefits, and other implications of the proposed legislation.
Instructions to Counsel. The detailed document prepared by a sponsoring department setting out what a bill needs to achieve. Sent to the Office of the Parliamentary Counsel as the basis for drafting.
Money Resolution. A motion required in the Commons for any bill with public spending implications. Must be passed before the bill can proceed to Committee Stage.
Office of the Parliamentary Counsel (OPC). A specialist office within the Cabinet Office whose lawyers draft government bills. Distinct from departmental legal teams.
Parliament Acts. Legislation passed in 1911 and 1949 that allows the Commons, in limited circumstances, to enact bills without the Lords' consent.
Ping-pong. Informal term for the process by which a bill moves back and forth between the Commons and Lords until both Houses agree on its final text.
Programme motion. A procedural motion setting out the timetable for a bill's progress through the Commons. Allows the government to allocate specific amounts of time to each stage.
Royal Assent. The Monarch's formal approval of a bill. Once given, the bill becomes an Act of Parliament.
Statutory Instrument. A form of secondary legislation made by a minister under powers granted by an Act of Parliament.
For the authoritative procedural source, Parliament publishes its own guide at parliament.uk. For more detailed treatment, the House of Commons Library briefings on legislative procedure are excellent and free to access. The standard work of reference for serious procedural questions is Erskine May.
This page is a general explainer of UK parliamentary legislative procedure. Procedure occasionally changes; this page is reviewed annually. For procedural questions about a specific bill, consult the official record on parliament.uk.
See also: How we source and present statistics