Just_Guessing - 9:35 am on Mar 8, 2005 (gmt 0)

1)pages hosted in the region(server based in uk) 2)Pages with region specific extension(co.uk for uk search) 3)the pages getting inbound links from the pages hosted in a specific region or having region specific extension.

As far as I know, you must have either 1) or 2) to be included in the "Pages from the UK" search. 3) may improve your ranking, but you will be filtered out without 1) or 2).

To be more accurate, 1) means having a UK registered IP address. Physical location is not important.

I don't believe that 1) or 2) in themselves are sufficient to improve your rankings in a "All the Web" search in google.co.uk