Most of the google earth images were taken circa late 2001, as a first pass of the UK.
( the half built conservatory in our garden being a huge clue)
They've re-visited some UK cities again, but nothing hugely new.
They updated a ton of the UK maps in detail but its still old detail ( check 'the gate' in Newcastle) which is a building site, but in reality its been open >3 to 4 years