Torchwood: Children of Earth was watched by 5.9 million viewers, according to unofficial overnight figures. The programme was the 5th most watched programme of the day and the 2nd highest rated on BBC1, being beaten by the three main soaps. The programme won its timeslot with an audience share of 25.8%.
An additional 97,000 people watched the programme in HD on the BBC HD channel.
The BBC Three repeat at 2345 was watched by 214,000 viewers, a 3.9% share.
Final figures will be available in two weeks time.
Torchwood continues Tuesday evening on BBC1.