Are you using the 'UK' search option? Perhaps they are using a different starting page. eg. google.ca is the canadian one. We have google.co.uk. They will probabbly be mostly the same but, there are also likely to be some differences.
Google (like most other search engines) uses your IP address to work out which country you're in. It's a fairly low priority bit of information when it comes to displaying results but if, say, Google finds several thousand sites which match your input data, then it will use your geographical location to try to sort results so that you're provided with the most appropriate links near to the top of the list.
Completely agree with Chris here. Google (to us) will always give results which show an obvious UK bias. They're showing results based on the fact that you're in the UK - which they can detect from your IP address.
If you carry out the same search from California then you'll get different results. Makes perfect business sense.