I'm tending to come to a slightly different conclusion to the one in Jeff's answer.
Before I state my answer, let me state my bias, as I most certainly am biased! I am based in the UK, and I develop some hardware but my primary job is software - I know very few people who have done much hardware development. I have struggled a lot to find good suppliers for both components and PCBs.
I would argue that it's not a generic shopping question, and that there is some value - their are a relatively small set of good generic component suppliers in the UK (or that are well setup for dealing with UK orders), and some of them are hard to find. It took me almost 6 years to find a good UK source for prototype/small run PCBs (fwiw, prototypes at Spirit Circuits for free and small runs through their ebay store). I only discovered mouser and digikey after asking some people who had been in the industry a while. Some of the best suppliers hardly advertise, and some of the best ones have poor or even non-existent websites (eg. another one that took me years to find, a cheap & fast place for custom machined plastic enclosures, BCL Distribution).
I do however agree with Jeff that it wasn't the best question, but I would say it would have been better to edit it to make it a better question rather than leave it turning up in searches as a closed answer that no one can now improve. An example of what I think would be a better question is "Where do engineers in the UK usually go when they're trying to obtain fairly generic components for building prototypes or small runs?"
In a lot of ways, it's a very similar question to "Which is the best C++ compiler?" - these suppliers are our essential tools of our trade, using the correct one can make a huge difference to a project.