Sorry, Ratboy, I wasn't really clear enough. I'll try again!
I used the Google Keyword Tool to check search volumes for a specific keyphrase. The results returned showed the local search volume (UK only) returning over double the search results when compared to the global search volume (the world). How could this be, since the UK is, I assume, part of the world? Surely local results could only ever be a fraction of global ones, except in a rare case where they might be equal (say if a word or phrase is specific to one country).