11 secrets from X Factor 2015's Six Chair Challenge

Here's the secrets I uncovered from being inside the arena for this year's filming...

1. There’s a lot of booing

The crowd very much is the fifth judge. If they don't like an act, cover your ears. The Wembley audience is not a forgiving one.

2. Simon wants to know what everyone thinks

Mr Cowell loves a rowdy crowd. It’s always one of the first things he tells an audience: misbehave, make noise, make yourselves known. These people, who’ve queued for hours to sit inside Wembley, will be the ones buying the winner’s records after all. He wants to know what they think. In fact, he's got this sort of 'robot'-style scan that he does, checking to see how the audience are reacting all around Wembley: is it 'must download this song right now' or 'I never want to hear that again'? It's his very own clap-o-meter.

3. The crowd knows what to do

They don't need any guidance on how to behave during the Six Chair Challenge. If a singer is good, you yell “SEAT”. If the singer is good and there aren’t any seats left, you yell “SWAP”. Then you decide which current seat owner you want to get rid of, so you start holding your fingers up to dictate which number seat should be sent packing. If you and your friends disagree, based on my experience of watching the people in front of me, you then start having a finger battle and try to shut your friend down. If you don’t like someone at all, you yell “OFF OFF OFF”. And, of course, if someone gets kicked out that you do like, you continually yell “BRING THEM BACK” until the judge changes their mind. I’d say the show should come with a rulebook, but it doesn’t need it. Everyone falls in line and the entire arena is very vocal.

4. The Wembley audience has power

You’d think being the successful music mogul that he is, Cowell would brush off the boos of a crowd. He knows exactly which singers should make it through and which shouldn’t, right? Well, actually, he’s happy to admit when he’s wrong. The angry chants of Wembley actually forced a U-turn out of the judge this year as he admitted, “You own up to your mistakes” when he brought a fan favourite back. Even the bemused act had to thank Wembley for working so hard on his behalf.

5. Cheryl's created a squad

You’d be forgiven for thinking Cheryl simply drafts her mates in to sit behind the judges and help make her decisions. She’s always turning around to see what those in the crowd behind think, pulling faces when they disagree with her or urging them to cheer more. But they’re just members of the public. Get near the front and you’ll be in the crew.

6. There’s a lot of head holding from the judges

The Six Chair Challenge is tough for the singers, but it’s tough for the judges too who are making decisions in front of a riled up 5,000-strong crowd. They spend a lot of time with their head in their hands, holding their hands up or looking up at the ceiling as if the answer might be up there somewhere. No wonder Cheryl wanted this section of the audition process dropped altogether.

7. The panel wind each other up

Judges teasing each other is nothing new – it’s part of the pantomime of reality shows – but they also have no problem using the crowd to wind one another up. As Simon pondered his decisions, Rita Ora was secretly holding her own hand up to the crowd, encouraging them to join in her calls to get rid of a certain singer. Maybe Rita’s helping him build the right category, or maybe she's playing with his decisions so her category is stronger? Time will tell.

8. Two crowds are better than one

Six Chairs is a long process and filming often continues late into the night. The crowd therefore gets swapped from an afternoon to evening one, so you might not always see a full category chosen. We pondered here whether it might be a smart move by producers to help keep some of the line-up a mystery – after all there's a bit gap between filming and when this part of the X Factor is on screens – but show insiders say it's simply a matter of time and filming just overruns. Nonetheless it's a good way to freshen things up. There’s only so many hours you can sit on a plastic flippy chair and cheer for another rendition of an Ed Sheeran hit, after all.

9. The acts support each other

Sure it’s a competition, but when a good act comes on, even those fighting to stay in their chair respond. Grimshaw was shocked to see a full standing ovation from one group, as a singer (to use Cheryl's words) "took the roof off of Wembley". One singer came extra prepared with a Union Jack-patterned hanky ready to dish out when the tears started flowing. It was also a handy flag to wave around when Wembley was pumping.

10. New co-host Olly comes with a ready-made chant

Warm up comedian Ian Royce need only say “Olly, Olly, Olly” and the crowd will respond: “Oi, oi, oi!” He tried it with Caroline – “Cazza, Cazza, Cazza” and everyone just stared back a bit confused. We’ll find one for you too, Caroline, don’t you worry.

11. The judges and presenters’ other commitments continue

Hats off to Ms Flack who, on one day, dashed between her X Factor commitments and a recording of her champion’s dance on Strictly Come Dancing's recent launch show. DJs Nick Grimshaw and Xtra Factor’s Melvin Odoom also had to be up bright and early following a late night of filming, while Rita Ora dashed between jobs, arriving late to the Wembley panel on the day I sat in. “It’s not about me,” she said to an act as she ran in, before waving to the crowd, which amused Grimmers: “Oh, it’s not about me, but hey Wembley!”

The X Factor Six Chair Challenge starts Sunday at 7:00pm on ITV