MPs once had to put on top hats when raising points of order during debates
Clapping is officially still banned in the Commons, but is now tolerated
MPs do not address colleagues directly or by name in the Commons - they talk to the Speaker and refer to Honourable and Right Honourable friends, gentlemen and ladies
Male MPs outnumber women in the Commons by four to one
The more powerful of the two Houses of Parliament, the Commons is the main debating chamber of MPs - the Members of Parliament elected by the country's voters.
Each of the 646 MPs represents a constituency. Most are members of one of the main political parties, but there is usually a handful of independents.
Once elected, MPs will normally serve for the lifetime of the parliament - a maximum five years - before the next general election, when they can stand for re-election, in some cases subject to their reselection as a candidate by their party.
The prime minister decides when, within the five-year term, to hold a new election.
The Commons is the most important place for discussing policies and making laws.
All bills must go through both Houses before they become law, but although the Lords also scrutinises proposed legislation, MPs have the final say.
As long as a prime minister retains the support of the party's MPs and can win all the key parliamentary votes, he or she should be almost unassailable.
However, if enough MPs vote against the government to defeat it in the ultimate test of a censure motion or a no-confidence motion, that government will fall and the PM will have to resign.
That hasn't happened since 1979 when James Callaghan lost a no-confidence motion to Margaret Thatcher by a solitary vote.
Proceedings in the Commons are controlled by the Speaker - an MP chosen by MPs to chair debates in an even-handed way. For that reason, once chosen, he or she must no longer represent a party.
Parliamentary material is reproduced with the permission of the Controller of HMSO on behalf of Parliament.