Luther concluded its short run with just under 5 million viewers on Tuesday night.
The Idris Elba drama thrilled an average overnight audience of 4.77m (21.5%) at 9pm, dropping around 200,000 from last week. Earlier, Celebrity Mastermind quizzed 4.04m (20.1%) at 7pm.
On BBC Two, University Challenge brought in 2.49m (11.9%) at 7.30pm, followed by MasterChef: The Professionals with 3.34m (15.6%) at 8pm. We're Doomed! The Dad's Army Story appealed to 2.67m (12.0%) at 9pm, while QI tickled 1.60m (8.6%) at 10pm.
Channel 4's How the Rich Live Longer fascinated 1.22m (5.7%) at 8pm (164k/0.7% on +1), while Supervet at Christmas was seen by 1.68m (7.6%) at 9pm (288k/1.7%).
On Channel 5, The Dog Rescuers at Christmas attracted 1.00m (4.7%) at 8pm, followed by Michael Buble's latest Christmas special with 956k (4.3%) at 9pm.
Finally, Tattoo Fixers returned on E4 with 607k (2.7%) at 9pm (227k/1.3%).
