Prime minister’s questions in the House of Commons typifies British democracy in some respects. It fulfils an essential function by means of convention, and it often promotes theatrical performance over legal substance. Executive power wielded from Downing Street is wide-ranging and, if the incumbent commands a large parliamentary majority, hard to check in practice. But prime ministers cannot hide from interrogation by MPs. Their strengths are proven and their weaknesses exposed. Boris Johnson has not feared Jeremy Corbyn in that arena and will not face the outgoing Labour leader again after Wednesday’s session. The valedictory exchanges were true to type for each man. Mr Corbyn raised important issues regarding the coronavirus response, but without forensic rigour. Mr Johnson gave responses too void of information to qualify as answers. The weekly routine of hurling barbs across the despatch box is not often edifying. David Cameron once pledged to end “Punch and Judy politics”, but failed to stop the pantomime element. Mr Corbyn has tried to change the tone, introducing questions sent to his office from members of the public – an innovation that was mocked in Westminster, although it did expose some of the vacuity of the usual proceedings. But the Labour leader’s unfocused method has given successive prime ministers an easy ride. Tory whips have eased their leaders’ burden by planting soft questions with sycophantic MPs who, for example, invite the prime minister to join them in celebrating the government’s achievements. Another unwelcome habit is the tendency to deliver micro-speeches for use later as self-promoting digital clips. The Commons was overly theatrical before MPs started using it as a stage scenery for their Facebook campaigns. Parliament is also host to erudite speeches and great acts of persuasion. Much of that goes unnoticed because PMQs has the higher profile and showcases the worst, not the best. A civil, respectful debate on the coronavirus bill earlier this week was a better spectacle because it was unspectacular. MPs were thoughtful and measured in grappling with the dilemma of how to restrict public activity without suffocating civil society. Partisan hostilities were suspended. Government by perpetual consensus is not possible. Robust debate in an oppositional system can protect against excess cosiness in the political class, but a crisis such as the one currently unfolding also illuminates the ground where politics must transcend normal political battle lines. The adversarial style is not always fitted to times of national adversity, and at those moments the Commons is capable of encompassing disagreement over policy within an understanding of common political enterprise. Parliament breaks for recess at the end of this week and it is not yet clear how the legislature’s function in holding the government to account can be performed in a state of lockdown. That is a cause for concern, but there is reassurance in the disciplined and serious response of MPs to the crisis so far. The old institutions are imperfect but robust, anachronistic at times but creative in extremis. It is easy to find examples in recent years of Westminster politics at its worst, but rising to the present challenge can also be a moment when British democracy performs at its best.