The one that has lots of people saying "it's just clever accounting" "they don't mind about £10 here and there" "they only worry about the big guys not people like me" and then ends with We're coming to get tax evaders - make sure you've declared your earnings
I get that it's important to declare your earnings and I'm not in any way supporting cash in hand work or whatever, but this just feels like HMRC (yet again) targeting the little man because it's easy to intimidate people into paying with big scary adverts. And at the same time they're brokering deals with big companies who owe billions in tax to let them pay a fraction of what they owe.
Every time I hear that advert I shout think get your priorities straight!