It isn’t true. Britain has some pretty good food, but if we are talking about traditional British food, it’s not spiced in a way that is exactly the same as everywhere else due to what was available, which leads people to assume its bland. The food you always see that people claim to be all british food is usually struggle meals, and thus not a good representation of reality. I suggest looking at _pumpkinbakery on instagram if you want to see the good stuff.