Select committees: the most effective part of Parliament nobody votes for

The dramatic moments of British politics happen at the despatch box, but the substantive ones increasingly happen in committee rooms up the corridor, where a panel of backbenchers questions a chief executive who would rather be anywhere else. Select committees have become the most consistently effective scrutiny machinery Westminster has, and how they got that way is a story worth knowing.

The structure is simple. Each government department is shadowed by a Commons select committee of backbench MPs, with party balance reflecting the House but with no ministers among them. Committees choose their own inquiries, summon witnesses, demand documents, and publish reports to which the government must respond within two months. Alongside the departmental set sit cross-cutting heavyweights, above all the Public Accounts Committee, which has audited government spending since Gladstone and works from the National Audit Office's investigations.

The transformation came in 2010, when chairs stopped being handed out by party whips and became elected by secret ballot of all MPs, with salaries attached. That single change created a career path in Parliament that does not run through ministerial patronage. A capable MP can now build a decade's reputation on scrutiny, and chairs regularly matter more to public debate than the ministers they shadow. Committee members hunting in cross-party packs, sharing lines of questioning in advance, have produced the hearings the public remembers: media owners, bank chiefs, retail tycoons and tech executives answering, under privilege, questions no interviewer could compel.

What the power amounts to

Formally, committees are weak. They cannot legislate, cannot enforce recommendations, and their power to compel reluctant witnesses rests on parliamentary privilege that is rarely tested to destruction. Ministers sometimes decline to appear; papers are sometimes refused. Their actual force is reputational and evidential. A unanimous, evidence-heavy report from a cross-party committee is hard to dismiss as partisanship, and its recommendations have a documented habit of becoming policy a few years later, once the government can adopt them as its own. Pre-appointment hearings for major public roles, post-legislative reviews and the standing terror of the Public Accounts Committee's grilling all shift behaviour upstream, in the departments and boardrooms that would prefer never to testify.

For the interested reader, committees are also the most accessible part of Parliament. Every hearing is streamed and archived, every report published, and written evidence is open to anyone, meaning a member of the public with relevant expertise can put material on the parliamentary record by emailing it. The despatch box performs politics. The committee corridor, at its best, performs government's least glamorous necessity: making powerful people explain themselves, in public, sentence by sentence.