The third and final instalment of the Red Dhalia story pulled in an impressive 6.85m (25.2%) for ITV1, easily winning the 9pm hour. The first and second parts interested 6.74m (25.6%) and 6.52m (24.1%) on Monday and Tuesday respectively.
Elsewhere at 9pm, BBC One's New Tricks, which starred Hannah Waterman, took 3.85m (14.2%), Gordon Ramsay's F Word had 2.69m (9.9%) for Channel 4, and 2.37m (8.7%) watched Horizon: The Secret Life Of The Dog on BBC Two.
Five's NCIS repeat was last for the hour with 1.05m (3.9%).
Earlier, at 8pm, You've Been Framed attracted 5.06m to ITV1, 2.3m (8.7%) tuned in for Relocation, Relocation on Channel 4, and Natural World grabbed 2.28m (8.5%) for BBC Two.
Trial Of The Knights Templar averaged 1.19m (4.5%) for Five, while BBC One's My Family put in 4.44m (16.7%) between 8.30pm and 9pm.
Overall, ITV1 came top during primetime with an average share of 21% to BBC One's 19%. Channel 4 was third with 9.1% (+1: 0.8%), followed by BBC Two with 7.1% and Five's 4.2%.
Elsewhere, Sky1's Fat Families opened to 483k (1.8%) during the 8pm hour.
BARB ratings data supplied by Attentional