A switching rehearsal. Intro, push. Deco, push. Deco, push. Deco, push. Deco, push. That's someone practicing their moves prior to broadcast (weewooweewoo says "broadcast" but I'll bet this was only streamed, as indicated by the iPlayer bug)) and having it accidentally stream to the Internet. It's as simple as having one button out of a hundred lit up and you miss it, especially if you're only going to the Internet and there isn't someone sitting there going "oh shit we're live". Granted, it's usually a prominent button but there are a lot of buttons:
Civilians generally don't get to see this stuff. Doing one of these things live with manned cameras, talent, and the pressure of a live broadcast is fucking amazing. It's like this without the chaos. What you're looking at there is probably switched by that little guy. The stuff I work on starts in places like this.
Imagine the kinds of video games you can play with those. You can also probably run a one-man city-wide surveillance operation with those. *cue Person of Interest theme*
They've recently added an AI module to the iPlayer. They chose Tay.