What are you comparing it to? Compared to the US any many European countries, I've always thought graphic design in the UK tended to be quite tasteful and restrained.
Comparing it to my favourite countries in Europe. Portugal, Spain, Greece, Italy. All have more innovative and interesting visual design (for the most part).
Hmm, I certainly can't agree in the case of Spain. Spanish ads feel quite dated to me. There's obviously a subjective component here, so probably not much to discuss.