Hitwise today said that "Over one third of all UK Internet traffic comes from Google websites". Or, to be specific:
A custom category consisting of the 100 most visited web properties in the UK that are owned by Google Inc accounted for 36.55% of upstream traffic to all categories of websites in the UK during March 2008, up from 30.19% in March 2007.
Most of this ( 27.48%) came from www.google.co.uk.
The top 10 Google sites in terms of UK visits are in the table below (click for larger version):
