How a Bill Becomes a Law
What Is a Bill?
Before a new law is passed, it begins life as a Bill. A Bill is a proposal for a new law or a change to existing law. Most Bills are introduced by the government (called government Bills), but MPs and Lords can also introduce Bills privately (called private members’ Bills). Once a Bill has passed through all the stages in Parliament and received royal assent, it becomes an Act of Parliament — a law. The legislative process has several distinct stages and ensures that proposed laws are scrutinised, debated and (where necessary) amended before they come into force.
The Stages of the Legislative Process
A Bill typically passes through both the House of Commons and the House of Lords, though some Bills begin in the Lords. Each House considers the Bill through five stages: First Reading, Second Reading, Committee Stage, Report Stage and Third Reading. After both Houses have agreed on the same text, the Bill is sent for royal assent.
First Reading is a formal announcement that the Bill has been introduced. The title is read out and the Bill is printed. No debate takes place at this stage. It is purely procedural.
Second Reading is the main debate on the general principles of the Bill. MPs or Lords debate whether the Bill’s broad aims are worthwhile and vote on whether it should proceed. If the Bill fails this vote, it falls. The Second Reading is the most politically significant early stage — whips work hard to ensure their party’s members vote the right way.
Committee Stage is where a small group of MPs (a Public Bill Committee, or the whole Commons for certain constitutional Bills) scrutinises the Bill line by line. They can propose and vote on amendments to specific clauses. This is where the detailed work of legislation is done. External experts or affected groups may give evidence to the committee.
Report Stage allows the full House to consider the amendments made in Committee Stage. Further amendments can be put forward and debated. All MPs have the opportunity to contribute, unlike the committee stage which involves only selected members.
Third Reading is the final debate in that House. It is usually brief. MPs vote on the Bill as amended. If it passes, the Bill moves to the other House (Lords or Commons) and goes through the same stages again. If both Houses pass different versions of the Bill, it goes back and forth in a process called ‘ping-pong’ until they agree on the same text.
The five stages a Bill passes through in each House are: First Reading (formal introduction, no debate), Second Reading (debate on general principles, first vote), Committee Stage (line-by-line scrutiny, amendments), Report Stage (full House considers amendments), Third Reading (final debate and vote). A Bill must pass through both Houses before receiving royal assent.
Royal Assent
Once both Houses have agreed on the same final text of a Bill, it is sent to the monarch for royal assent. Royal assent is given on the advice of the government. By constitutional convention, the monarch does not refuse royal assent — the last time a monarch refused was in 1707. Once royal assent is given, the Bill becomes an Act of Parliament and comes into force, either immediately or on a date specified in the Act itself.
If the House of Lords rejects or significantly amends a Bill, it is returned to the Commons — a process sometimes called ‘ping-pong.’ The Lords can delay a Bill by up to one parliamentary year. Under the Parliament Acts of 1911 and 1949, if the Lords continue to block a Bill that has been passed by the Commons in two successive sessions, the Commons can pass the Bill without the Lords’ consent. This power is rarely used but exists as an important constitutional mechanism to prevent the unelected Lords from permanently blocking the will of the elected Commons. Finance Bills (relating to government taxation and spending) can only be delayed by the Lords for one month, giving the Commons much stronger control over financial legislation.
The role of MPs in the legislative process includes: debating the general principles of a Bill at Second Reading; scrutinising it line by line at Committee Stage and proposing amendments; considering further changes at Report Stage; and giving a final vote at Third Reading. MPs also represent constituents who may be affected by the proposed law, and may speak in debates to reflect local concerns or campaign interests.
Government Bills are introduced by ministers and are given priority parliamentary time. They form the bulk of legislation and usually reflect the governing party’s programme announced in the King’s Speech. Because the government controls the timetable, government Bills have a high success rate.
Private members’ Bills are introduced by backbench MPs or Lords. They are entered into a ballot and those drawn first get limited debating time on specific Fridays. Most private members’ Bills do not become law because they run out of parliamentary time, but some important laws began as private members’ Bills — for example, the Abortion Act 1967. A private Bill, by contrast, is different again: it deals with specific organisations or localities rather than the general public.
Why the Legislative Process Matters for Citizens
The staged legislative process exists to ensure that laws are considered carefully before they come into force. Each stage gives MPs, Lords and experts opportunities to identify problems, propose improvements and debate the implications for different groups. Citizens can engage with the process: by writing to their MP, giving evidence to a committee, petitioning Parliament, or joining campaigns that seek to influence a Bill’s content. Understanding how a Bill becomes law is fundamental to understanding how citizens can bring about political change through parliamentary channels.