A bill (draft law) can start in either the Commons or the Lords. The explanation below assumes it’s started in the Commons. If it starts in the Lords, the paragraphs where the headings say (Lords) come first.

First reading (Commons)

This is just a formality. The bill’s title is read out in the chamber and a date is set for the second reading. There’s no debate or vote at this stage, so you’ll never see them in Clear the Lobby newsletters.

Second reading (Commons)

This is the first chance for MPs to debate the bill. Typically, only its key principles are considered. At the end, MPs vote on whether or not to progress it to the committee stage. (The bill can also be progressed without having a debate first if MPs agree on it.)

Committee stage (Commons)

Now the bill gets looked at in more detail. A group of about twenty MPs called a Public Bill Committee is assembled, which goes through the bill line by line. They suggest and vote on any amendments (lines they want to add, remove or change). They may also speak to experts and relevant organisations outside Parliament.

Sometimes a Public Bill Committee isn’t used at this stage, and all MPs can take part. This is called a Committee of the whole House.

Bills that have been fast tracked by the government get less time at this stage.

Report stage (Commons)

The version of the bill that the Public Bill Committee came up with is presented to all MPs, who can suggest and debate more amendments.

Third reading (Commons)

This usually happens right after the report stage. It’s the last chance for MPs to debate the contents of the bill. They can’t suggest any amendments; the debate is just about what’s in the bill, rather than what could be included. At the end, MPs vote on whether to progress the bill to the House of Lords.

First reading (Lords)

Like in the Commons, just a formality. The bill’s title is read out with no debate.

Second reading (Lords)

This is the first chance for Lords to debate the bill and flag up any areas where they think amendments are needed.

Committee stage (Lords)

Lords go through the bill line by line and consider a list of amendments. Unlike in the Commons, the government can’t set a time limit for debate at this stage, or limit the topics that are discussed.

Report stage (Lords)

Detailed examination of the bill continues. Any member of the Lords can take part and votes on any amendments may take place.

Third reading (Lords)

This is a chance for Lords to put the finishing touches on the bill, making sure it’s effective, workable and without any loopholes.

Unlike in the Commons, amendments can be made as long as they haven’t been fully discussed and voted on already. These amendments often allow the government to fulfill any promised of changes that it made at an earlier stage.

Consideration of amendments

The bill goes back to the House it started in, so in this example, MPs in the Commons would consider any amendments that the Lords made. Both Houses must agree on the exact wording of the bill, so if the Commons makes changes at this stage then the Lords must agree on them too. The bill can end up moving back and forth several times (a process known as “ping pong”) until both Houses finally agree.

Royal assent

Once both Houses reach an agreement, the bill gets formal approval from the Queen and it becomes law! The monarch will always give their approval, acting on the advice of ministers.


This is politics, and there are always exceptions. One important one is money bills, any law that concerns tax at a national level, public money or loans. If a money bill passes through the Commons, it becomes law after a month whether the Lords approves it or not.

Another exception is the Salisbury Convention. This is where the Lords won’t vote down a law that the government had in its manifesto, the thinking being that it already has public support so it would be wrong for the Lords to overrule it.