Torchwood: Dead of Night achieved an average audience of 4.2 million viewers on BBC One and BBC One HD, according to unofficial overnight figures.
The third in the series had 18.8% of the audience share and was the 7th most watched programme of the day. It won the 9pm timeslot, with Single Handed on ITV1 watched by 3.1 million viewers.
The figure was slightly down on the last week, which scored an average of 4.4 million. The episode saw a drop in viewers during the hour from 4.6 million in the first quarter to 4.0 million in the final quarter
The final ratings for Dead of Night will be released next week and will include those who record the programme and watch it within seven days.
Mondays late night repeat of episode Two Rendition had 0.4 million watching.
Initial audience figures released for Dead of Night shown on Starz last Friday indicated that 1.1m viewers watched over its opening night; the premiere broadcast at 10:00pm was watched by 636,000 viewers, with its 11:00pm repeat seen by 382,000. This compares with an average of 976,000 viewers for Rendition's opening night.