Main Chamber - Project Open Gov

The principal debating chamber of either House of Parliament.

Category: Parliament and elections Parliamentary procedure

Also used as: main chamber, Commons chamber, Lords chamber, parliamentary chamber

Source / explainer: Read UK Parliament information on debates

Last reviewed: 21 August 2026

The Main Chamber is the principal debating chamber of either the House of Commons or the House of Lords. It is where many major debates, questions, statements, bill stages and votes take place. The term is useful when distinguishing chamber business from Westminster Hall debates, committee meetings or other parliamentary activity.

Related terms

House of CommonsThe elected chamber of the UK Parliament, made up of Members of Parliament.House of LordsThe unelected second chamber of the UK Parliament, which scrutinises bills and government policy.Westminster Hall DebateA Commons debate held away from the main chamber, usually on a general motion without a vote.