Ever wondered what goes into creating an episode of QI? Wonder no more...
QI is recorded in the evening, or sometimes late afternoon, but preparation starts early. The studio has to be transformed from an empty room to the fully functioning, perfectly lit (and hopefully structurally sound) QI set, complete with huge screens, buzzers, scoring equipment, and klaxons.
Seven cameras are needed to film QI: two camera operators on either side of the set filming the panellists; a ceiling mounted camera for wide shots; the centre camera pointing at Stephen, which has his autocue attached; and finally a jib (camera on a long swinging pole) with which we film the long sweeping intro shots through the QI titles magnifying glass.
In order to maintain the pristine world you see on television, all the surfaces have to be spotless. The entire studio floor gets a fresh coat of paint every morning, and the set is constantly touched up throughout the day to remove any unsightly blemishes that could show up on HD. Stephen and Alan are also freshly laminated for each episode to give them an extra sheen.
Once everything is up and running, rehearsals begin. Each show gets two quick run-throughs before recording, to ensure that everything goes as smoothly as possible on the night. Background images, lighting, sound levels, buzzers, science experiments, and most importantly, the questions and answers all need to be checked.
Stand-ins and QI Elves take the place of the panellists, and the first run-through is 'hosted' by the floor manager, Guy Smart. Stephen emerges from his dressing room after lunch, having assimilated an entire script of information in an astonishingly short time, and hosts the second rehearsal. By the end of the afternoon, we have a completely clued-up Stephen ready to take on four completely clueless panellists.
If there's time, the guests might get a quick practice on set before the real thing; the Elves usually prepare fake warm-up questions for them to try out before we start recording, so they're not going out completely cold.
QI scripts comprise of around 16 questions for Stephen to ask the panel, and a set of notes for each one that contain all the interesting facts. Everything else on the show is ad-libbed.
The buzzer sounds are picked by the 'curator' of the episode (the Elf who compiled the script) and QI creator John Lloyd.
Meanwhile, a growing crowd of dedicated QI fans has been growing outside the studio, hopefully in an orderly queue. Outside of Top Gear, tickets for QI are the most sought-after in the entire BBC, so people sometimes turn up and wait for hours for the best seats, relentlessly upbeat and presumably bunking off work.
When everyone's in their seats and the panellists have all been through make-up, Stephen introduces each panellist one at a time for a pre-show chat and mike test, and then some audience shout-outs and his traditional Audioboo challenge.
Cameras start rolling at 4.30pm for afternoon recording and 7.30pm for evening ones, and each recording is two hours long (each of which gets edited down to 30 and 45 minute shows).
Surprisingly, watching a live episode isn't that different from the finished result - the panellists have to be very quick-witted all the way through, so the pace is as fast as on TV, and there are usually only one or two quick re-takes to do at the end for technical reasons. Of the 16 questions in each script, 8 or 9 make it into the final broadcast.
Assuming nothing's gone terribly wrong, by 10 o'clock the cameras are off, the QI set is packed up and back in storage alongside the Have I Got News For You and Graham Norton sets, the recording tape is safely inside a reinforced briefcase handcuffed to the producer, and everyone has retired to the green room bar.
It's that simple.