Backstage at the BGT rehearsals: fake winners, stand-in judges and dressed-down Ant and Dec

One-by-one the performers get a taste of what it’s like to be voted out – ie, have a red light shone on them – and some even find out how it feels to make it into the top three, or even to be named winner.

On the panel, the fake judges pretend to give Amanda, Simon, Alesha and David’s thoughts, even sending the vote back to the public decision. The stand-ins tend to be runners working on the show, and at times they’re even asked to walk out of the doors at the back to practice the judges’ entrance. “They wear stickers to say which judge they are,” a show insider told me.

There are no stand-ins for Ant and Dec, although they do rock a more ‘off-duty’ look than their polished live show style. There’s only so long one can be bothered to wear a three-piece suit, right? The hosts are certainly kept busy, with rehearsals running throughout the day, before a quick change and onto the live show.

In between the camera checks, make-up and run-throughs, the wardrobe department is also working at high-speed. Outfit changes can happen as late as forty minutes before transmission. And with bigger and bolder outfits than their first auditions there's a lot to decide for each of the acts.

As a bystander it feels like there’s a whole lot to get done, but having seen just what these guys can achieve in a thirty-second advert break, it’s no wonder it all comes together so seamlessly on the night.

Britain’s Got Talent continues tonight at 7:30pm on ITV