The trouble with taking so many American TV programmes is that people replace some of their cultural heritage with that of the US. I don't know that many people under 30 would know what "berk" meant in English slang.
It's Cockney rhyming slang. Berkshire Hunt rhymes with ... .
We see the same thing with youngsters sticking up a middle finger, when the traditional UK version uses two fingers. You can't snarl "up yours!" with a middle finger; all I've ever heard accompanying it is "sit on this!", but then I don't watch much TV.
Mind you, I'm not a Cockney, either.