This stage normally starts at least two weeks after Second Reading. All Bills in the Lords normally go to a Committee of the Whole House, which, as the name suggests is a committee taken on the floor of the Lords. On occasion, Bills may be sent to a Grand Committee – an increasingly common practice.
All peers may table amendments to the Bill, which are subsequently grouped for debate. The Bill is debated clause-by-clause, with each clause requiring endorsement even if there is no debate on it. The Committee Stage may take up several sitting days, which need not be consecutive. Amendments are moved and debated and agreed or disagreed. Divisions may be taken.
When the Committee of the Whole House has concluded its deliberations, it reports the Bill, with or without amendments, back to the House.
Procedure is almost identical when a Bill is sent to Grand Committee – any peer may table amendments and attend. The only difference is that divisions may not be taken. Differences of opinion must be held over until a later stage if a vote is required. A Grand Committee sits in parallel to the House, so it must break for any divisions called during the progress of business in the main chamber.