The three-part drama series, about a person who wakes up from an alcoholic blackout to find he has nearly killed a man, attracted 4.47m (19.6%) in the 9pm hour.
Meanwhile, ITV1's Real Chariots of Fire drew 2.01m (8.4%) despite an 8m lead-in from Coronation Street, and Undercover Boss returned with a decent 1.8m (7.9%) and 292k (1.7%) on Channel 4 +1.
BBC Two's 90-minute 7/7: One Day In London took 1.56m (7.2%), while Big Brother logged 1.24m (5.5%) for Channel 5 and 144k (0.8%) on timeshift.
The Walking Dead rallied over a thousand viewers to reach 861k (4.8%) on Five at 10pm, but marginally lost out to Channel 4's Daredevils: Life on the Edge, which dazzled 869k (5%) and 126k (1.4%) on +1.
Panorama's investigation into cold callers interested a higher-than-usual 3.6m (15%) at 8.30pm, while Jamie's Summer Food Rave Up served up 945k (3.9%) on Channel 4 (+1: 128k/0.6%).
Overall, BBC One nicked a primetime victory with 19.3% against ITV1's 18.9% (+1: 0.7%). BBC Two earned a third place finish with 8.7%, which was ahead of Channel 4's 4.6% (+1: 0.8%), and Channel 5's 4.1% (+1: 0.4%).
For the third day in a row, ITV3 managed to surpass the million viewer mark in the 9pm hour, this time with a classic episode of Taggart which mustered 1.04m (4.1%) and was the night's most-watched multichannel programme.
Sky Atlantic's Alan Partridge on Open Books with Martin Bryce amused just 137k (0.6%), after which Armando Iannucci's Veep slumped to 43k (0.2%), and Brand X with Russell Brand opened with 27k (0.3%) at 11.05pm.
BARB ratings data supplied by Attentional