The ratings are in and while not as strong as I expected...good news 
UK early ratings for Doctor Who is often low for the 1st call so expect this to go up. Also great news that over 1 in 3 people watching TV had Doctor Who on the screen. BBC I Player and repeat viewings will proibably be healthy too...
No surprised a drop but since 5 million is a hit in the UK there is no worry and WOM will push the series up as it contiues in my opinion.

Doctor Who launched to 8 million viewers and a 36.90% share according to the BBC.
UK early ratings for Doctor Who is often low for the 1st call so expect this to go up. Also great news that over 1 in 3 people watching TV had Doctor Who on the screen. BBC I Player and repeat viewings will proibably be healthy too...
Rival ITV with Harry Hill’s TV Burp hit 3.5 million viewers (down 40% in overnight figures on the previous week)
David Tennant finale scored 10.40 million viewers,
Season 1 [2005]: 9.9m
Season 2 [2006]: 8.0m
Season 3 [2007]: 8.2m
Season 4 [2008]: 8.4m
Season 5 [2010]: 8.0m
No surprised a drop but since 5 million is a hit in the UK there is no worry and WOM will push the series up as it contiues in my opinion.