The Guardian.UK explains what happened:
According to the BBC, they received thousands of angry complaints about the poorly-timed advertising. "We apologise for the timing of Saturday night's trail." said a spokesman.
Looking at the image above, it seems to be nothing compared to the eye rape that American TV has been doing to TV shows for years.
In in the US, its known as a "lower third" - though it seems every year that networks seem to keep making them bigger, taking up more and more real estate on the TV screen. And every year they become more eggregious, with characters moving around, flashing lights, explosions, etc. anything they can possibly do to detract from the show you are trying to watch, in an attempt to convince you to watch the next thing.
Its one more reason why I can't stand commercial television.