Re: More acceptable in America...
I always remember the episode of "Angel" with Wesley and Angel on a motorbike (Cordelia half-inched Angel's motor IIRC).
When they went to set off, Wesley presented Angel with a crash helmet, which Angel refused to wear on the grounds that it was pink and he was immortal anyway so it didn't matter. An argument ensued over the inconvenience of being stopped by the law. Matters were resolved by Wesley saying: "Stop being such a wanker and put it on.". Stress on the word "wanker" too.
As I heard it, this came about as the director wasn't happy with the script and wanted something more argument-endingly pithy. He asked Alexis Denisof for a candidate English (he worked over here for several years) epithet for someone making such a fuss over nothing. He responded: "Oh, I'd probably call him a wanker". A brief check of the "naughty words" list revealed that "wanker" wasn't on there, so in it went.
I sprayed tea all over the table in disbelief when it aired in the early evening on Sky 1.