A major launch
The premiere drew an overnight audience of 8.2 million and a 34% share on 22 April 2007. Its consolidated figure in this guide is 8.55 million. The Guardian described it as Stephen Fry’s first major ITV drama role since Jeeves and Wooster.
Series averages
Using the 18 historical totals in the archive, Series 1 averages 6.59 million, Series 2 averages 5.66 million and Series 3 averages 4.99 million. The decline is real, but it is not evidence by itself for one particular cancellation decision.
The final episodes
The Series 2 finale won its slot with a reported overnight audience of 5.3 million and 21%. The final broadcast in July 2009 attracted 4.8 million overnight viewers and the same share, also winning against its principal BBC One drama competition.
What the numbers do not prove
ITV publicly said the series had performed well while explaining that it refreshed its balance of returning and new drama. Ratings form part of the context; they do not establish a secret threshold, production dispute or single cause.