We are indeed a bunch of ignorant idiots when it comes to foreign languages. However, I also feel that the level of foreign language teaching offered in the U.K is on average, quite terrible.

To address your post, yes I would say by and large we are. However,it is not a one size fits all shoe, I consider myself fluent in Mandarin (self taught, never attended any courses whatsoever). I was best at German at school, hated french, liked conversational spanish. Isn't Spanish the 2nd most spoken language after mandarin chinese? Yes, it is shameful that more in the UK don't know more of foreign languages.

http://www.businessinsider.com/afp-mandarin-compulsory-as-portuguese-town-seeks-foothold-in-china-2014-11

In portugal (above url), they have chinese teachers or teaching assistants now. Those portuguese kids will probably be fluent long before british kids ever will be.