The latest episode on Wednesday night (March 27) only pulled in 790,000 (4.67%) at 10pm for the broadcaster.
BBC One won the primetime ratings battle, with MasterChef cooking up 4.87 million (22.9%) at 8pm and Margaret Mountford's Pompeii documentary reaching 4.92m (21.8%) at 9pm.
On BBC Two, The Great British Menu attracted 1.74m (8.0%) at 7pm, A Very British Wedding gathered 1.29m (6.0%) at 8pm and Terry Pratchett: Facing Extinction had 771k (3.4%) at 9pm. The BBC Two figures don't include HD numbers.
ITV's Wednesday night lineup still continues to struggle with Simon Cowell's Food Glorious Food only bringing 2.53m (11.9%) at 8pm, and drama series Lightfields only had 3.29m (14.5%) at 9pm.
One Born Every Minute brought 1.98m (8.7%) to Channel 4 at 9pm, while Terry Mynott's The Mimic had 664k (3.7%) at 10pm.
Channel 5's evening included Rolf's Animal Clinic, which had 1.02m (4.8%) at 8pm, NCIS, which drew 1.46m (6.4%) at 9pm, and Law and Order: SVU, which brought in 816k (4.8%) at 10pm.
BBC Four secured big numbers with Secret Knowledge, which intrigued 749k (3.5%) at 8pm.
Meanwhile, E4's teen drama Youngers collected 397k (1.76%) at 7.30pm.
BARB ratings data supplied by Attentional