How a bill becomes an Act of the UK Parliament

A headline says the House of Commons has passed a bill. Does that mean a new rule starts tomorrow? The bill may still have to go through the Lords. Even once it becomes an Act, the provision in the headline may have a separate start date. You can check both questions in the public record.

A bill is a proposal to make or change a law. This guide follows the usual route for public bills at Westminster. Some bills follow special procedures.

How a bill moves through each House

Most bills can start in either the Commons or the Lords. First reading formally introduces the bill. At second reading, the House considers what the bill is trying to do. At committee stage, members examine the wording in detail and consider amendments.

Report stage gives the House another opportunity to consider changes. Third reading is a final look at the bill as a whole. The Commons bars amendments at this stage, while the Lords can consider limited changes.

The other House then considers the bill. If it changes the text, the amendments go back to the House that considered it first. The wording can go back and forth until both Houses agree on the same text. This exchange is sometimes called parliamentary ping-pong.

When an Act comes into force

After the parliamentary stages are complete, Royal Assent is the monarch’s formal approval. The bill becomes an Act. Different sections of that Act may take effect on different dates.

Imagine an Act that sets up a register and requires certain reports to be filed. The section authorising the register might start on Royal Assent, while the reporting requirement begins on a date set later. The fictional example shows why the date that matters depends on the section you’re reading about.

Look for the Act’s commencement provisions, usually near the end. They tell you which sections start immediately, which have specified dates and which may be brought into force later. If a provision leaves the timing to a minister, look for a commencement order or regulations that set its start date.

Three checks when a headline says a bill passed

• Find the bill by title in Parliament’s bill directory. Check which House it is in and the most recent stage it completed.
• Check the latest published text. An amendment can change the wording that an earlier report described.
• If it has received Royal Assent, find the section relevant to the headline and check its commencement. Different provisions can start at different times.