If you’ve subscribed to Clear the Lobby for a little while, you’ll have noticed that some weeks there’s a deluge of bills scheduled for debate on a Friday. These are private members’ bills: legislation introduced by MPs and Lords who are not government ministers.

Private members’ bills are an opportunity for backbenchers to pass laws, but because they’re not allocated much time to be debated they rarely pass all the necessary stages to become law. (Between May 1997 and July 2017, only 117 private members’ bills received royal assent.)

Nevertheless, they’ve brought about significant changes to the law, such as the abolition of the death penalty and the legalisation of abortion. And even if the bill doesn’t become law, it’s an opportunity for non-government minister to raise an issue in Parliament and possibly affect legislation indirectly.

House of Commons

MPs must submit the title of their bill and a short description. They don’t have to publish a full draft. Thirteen Fridays a year are then allocated for debate.

In the Commons, there are three ways of introducing a private members’ bill:

1. The ballot

Once a year, there’s a ballot of all the backbench MPs and Lords who want to introduce a bill. Normally, the first seven drawn are likely to get a day’s debate. (Here’s a BBC News article about last year’s draw.) Bills introduced by ballot have the best chance of becoming law because they’re allocated the most time for debate.

2. Ten minute rule

Some bills in Clear the Lobby newsletters are presented in this way. Members have ten minutes to make their case for a new bill, which can be opposed by a similar speech. If it’s successful, the bill is scheduled for a second reading.

3. Presentation

Members formally introduce the title of the bill, but don’t speak in support of it. These stand the least chance of becoming law, but it hasn’t stopped MPs from going to great lengths to introduce bills this way. Last year, two MPs slept in the Houses of Parliament for three nights to be at the front of the queue.

House of Lords

In the Lords, private members’ bills are introduced through an annual ballot. Peers must submit a draft of their bill (including its title, a brief description and all the clauses and schedules) to the Legislation Office. The ballot decides the order in which the bills will receive their first reading, but after that debates are scheduled by the Whips Office.

Private members’ bills are usually debated one Friday a month.