Is food/gastronomy in the UK as bad as people claim it to be?

I've always heard and read in several discussions/comment threads that when it comes to food, UK is not the best place to consider if you're expecting a foodgasm... Is this true to some extent? I've only been in the UK for a week on vacation (London) and every restaurant I went to was just... alright and comparable to the food served in here (Portugal) even though we have our specialties that I would never exchange for the traditionally British Fish and Chips (Only truly British food I've tried whilst in London). So... What are your thoughts? It'd be interesting to see opinions from people who went to the UK on vacation/Currently living there but coming from another country, given that people who lived there all their lives are naturally used to it! :)