A committee of the whole House is a procedure in the House of Commons where the detailed, clause-by-clause scrutiny of a bill, known as its committee stage, takes place in the main chamber rather than in a separate committee room. This allows every MP to participate in the debate and propose and vote on amendments.

The procedure is traditionally reserved for bills of significant national, constitutional or financial importance, which are considered to require the attention of all 650 MPs. It is also used for emergency legislation.

How a committee of the whole House operates

The primary reason for holding a committee stage on the floor of the House is to ensure that legislation of the highest importance receives the widest possible scrutiny.

A standard public bill committee is composed of a small number of MPs with a specific interest in the bill; a committee of the whole House, on the other hand, allows any of the 650 MPs to contribute their views and propose changes.

When the House sits as a committee of the whole House, the serjeant at arms moves the ceremonial mace from its position on top of the clerks’ table to a bracket underneath it. The mace is a symbol of royal authority in parliament and signifies that the House of Commons is in session. Once the mace is relocated, the House is in committee.

There are also crucial procedural differences:

• Chairmanship: The proceedings are not chaired by the speaker. Instead, the chairman of ways and means, one of their two deputies presides over the committee, or a member of the panel of chairs presides.
• Participation: Any MP can attend, speak and vote. In a standard public bill committee, only the appointed members participate.
• Speaking rules: An MP may speak more than once on the same question, they also do not need to write to the speaker in advance. If they wish to speak, an MP should rise when the previous speaker has finished and try to catch the chair’s eye.

Erskine May, the authoritative account of parliamentary procedure, states: “Whenever an order of the day is read for the House to resolve itself into a committee on a bill, or when the House decides that it will immediately resolve itself into such a committee, the speaker is directed… to leave the chair without putting any question unless there is an instruction to be disposed of first.

“The mace is then placed under the table, the chairman of ways and means, or one of the deputies, takes the seat at the table and, after the clerk reads the short title, the committee begins the consideration of the bill.”

MPs can table and debate amendments to each clause, and divisions (votes) are held to decide whether to accept or reject them. Each clause must be agreed to, amended or removed and new clauses may be proposed and agreed to.

Once all clauses have been considered, the chairman reports the bill, with or without amendments, back to the House. The mace is returned to its place on the table, and the speaker resumes the chair, signifying that the House is no longer in committee.

The bill then moves on to its next legislative stage: report stage.

Which bills are considered in a committee of the whole House?

The procedure is usually reserved for the following categories:

• Bills of major constitutional significance: Legislation affecting the fundamental nature of the state. For example, the European Communities Bill (1971-72), and European Union (Withdrawal) Bill (2017-19).
• Emergency or expedited legislation: Bills that must pass quickly, such as emergency public health or anti-terrorism laws. For example, the Banking (Special Provisions) Bill (2007-08).
• Key parts of the Finance Bill: By convention, the key clauses of the annual budget legislation, which set the main rates of taxation (such as income tax), are considered by a Committee of the Whole House.
• Uncontroversial or unopposed legislation: This includes Consolidation Bills (which tidy up existing law) or Private Members’ Bills that have total consensus and require no debate.
• Other: When a bill is divided, the whole House debates only the most controversial parts (like “conscience” issues or choosing between alternative legislative schemes), while a smaller committee handles the technical details.