It's usually the tabloid-reading right (or the 'old right') that are moaning about how the UK is crap and had gone down the drain. You often find them harping on that everything was better in 'the good old days' (which invariably go totally undefined). That's just one section of the British right wing however, but easily one of the most embarassing...
The British 'left' is also quite broad but unfortunately has quite a few snot-nosed irritants who think they look clever by blindly attacking anything and everything about the country (and often rather insufferably delude themselves into thinking they're 'standing at odds' with their political 'oppressors'... Aaarrgghh!!!). Again, I think this section is more like the left wing's embarassing younger sibling.
These are, however, the two extremes. And like all extremes, they're wholly unrepresentative. I'd say the broad consensus in Britain is - while far, far from flag-salutingly proud - pretty patriotic, but not blindly or completely unswervingly so. I think that's pretty healthy.