The first half of the drama - part two airs tonight - had a solid 6.76m (27.7%) for the network between 9pm and 10.30pm. It was comfortably ahead of BBC One's nature documentary Swarm: Nature's Incredible Invasions, which had 4.96m (19.3%) in the 9pm hour.
Above Suspicion also had more viewers than Lark Rise To Candleford, which returned for a second series last night. The Victorian drama, shown in the 8pm hour on BBC One, had a strong 6.29m (23.8%).
ITV1's The Royal picked up 5.36m (20.3%) for the 8pm hour, following on from a Harry Hill's TV Burp clip show, with 5.47m (21.2%). The Antiques Roadshow drew the best numbers of the day, pulling in 7.87m (31.3%) for BBC One at 7pm.
The Best Of Top Gear brought in 3.11m (11.8%) to BBC Two at 8pm, then The Antiques Rogue Show - a documentary about a family of con artists - picked up 2.23m (8.7%). A screening of the comedy drama Kinky Boots followed with 1.4m (9.1%).
The latest update from Celebrity Big Brother ensnared 2.85m (11.1%) to Channel 4 at 9pm, with a further 374k (2.2%) watching on Channel 4+1. A new series of The Sunday Night Project, this week hosted by Phil Spencer and Kirstie Allsopp, delivered 1.41m (7.9%) from 10pm.
Five's action thriller Eraser, starring Arnold Schwarzenegger as an agent for the US government, had 1.15m (5.4%) from 9pm.
ITV1 triumphed in primetime with an average share of 23.5% (last week: 12.9%) to BBC One's 22.9% (26.2%). BBC Two was third with 8% (16%), followed by Channel 4 with 7.5% (9.9%) and Five with 4.7% (3%).
More 4's usually popular Come Dine With Me marathon was even more popular this week, peaking with 891k (4%) at 6.55pm, the top multichannel audience of the day.
Reruns of the cooking show outrated Sky1's premiere of the second series of Gladiators, which had 695k (3.4%) in the 6pm hour.
ITV2's top audience was 633k (2.7%) for a repeat of Demons in the 8pm hour.
Ratings data supplied by Attentional