During the first ad break of Big Brother at about 21:05, a Channel 4 ident appeared (the music related one with the stage) and a female announcer (not the same person who introduced Big Brother - that was a fella) said "Now on Channel 4, an exclusive commercial break. At 11am yesterday morning, hundreds of rail commuters had a change of routine." They then showed a long advert for T-Mobile with people dancing at a train station, done in the style of a flash mob.
This reminds me of the live advert that Channel 4 showed a few months ago which also started with a Channel 4 ident.
I like this teaser video: http://uk.youtube.com/watch?v=Lw215gE6r2k Well, really, because at 0:24 it says they have hidden cameras, and uhm, having a camera lens and viewfinder of a professional camera poking out a sports bag on someones shoulder which they're looking through... not so much hidden.
It wouldn't surprise me in the slightest if T Mobile become the next Big Brother sponsor in the summer as bar one or two series', that is the main style of sponsor they go for and T Mobile haven't done it yet. Perhaps they were seeing how a long advert has an impact on sales during Big Brother before they make some kind of deal
It was certainly better than the Honda ad a few months back - and must say these ads are very effective - I know I watched throughout, most of which to see who was responsible for it. Not that I'll be signing up to T-Mobile though.
Ironically my train tonight was cancelled cause of someone jumping infront of a train somewhere up the line, got home rather irritated cause I'll have to reschedule plans, and within 10 minutes this advert came on to remind me where I should be!