The answer is the sheer preparation and work that goes on behind the scenes.

More than a dozen tv crew set up the stage with cameras, lights, sound systems and boom microphones hours ahead of the show. The 159 members of the audience were in place about two hours before the real recording began.

An hour before, there was a trial recording of a mock panel that took questions from the audience, to make sure the equipment, lights and everything else worked as it should.

That turned out to be a light hearted banter between the mock panelists and the real audience with questions ranging from 'is the smoking ban to blame for the recession' to whether India should have spent money on sending the Chandrayaan 1 spacecraft to the moon while there was poverty in the country.

The final preparation sees an untaped question to the real panel from the audience before the live recording begins.

In pictures: Question Time panel tackles Peterborough's hot topic.

Elsewhere online:
Question Time - BBC website.