According to the website " Standing on Old Park Lane since June 14th 1971, and proudly boasting a Mayfair neighborhood (note the American spelling) address, Hard Rock London was the first cafe where the classes mingled."

You'll have to excuse me if I question the veracity of that claim. I'm pretty sure that during the postwar 20s and again during World War II the class barriers broke down significantly. Leaving that aside, this was apparently the first of the Hard Rock Cafès. Supposedly they serve "delicious American classics", but I'm having trouble resolving that term.

The last time I was in a Hard Rock Cafe (in Sydney) the menu consisted of hugely overpriced, extremely mediocre hamburgers and not much else. I don't really regret missing the opportunity to go into this one.