British IPA in the 19th century did used to be strong and heavily hopped, like the American versions today. Big flavour/aroma hops went out of fashion in Britain at some point. Modern British 'bitters' or 'real ales' - cask or bottle-conditioned ales, typically are weak, malty and very conservatively hopped with British or Euro hops like fuggle, and hopped more for bitterness than aroma and fruity flavour. Because of the trendiness of the term 'IPA', many straight bitters like Greene King for example, have put "IPA" on the tin regardless of the fact that this style of beer isn't really an IPA.
Fullers do a reasonable British IPA at 5+ ABV and with mild hoppiness. But better look to some of the outstanding but expensive British craft breweries like The Kernel or Vocation, doing pale ales and IPAs that K Musselman would love. The Kernel in London was my introduction to hazy hoppy pale ale, which is now my favourite drink.
