Only 1.38m (10.2%) chose to watch the sci-fi drama's series-five climax at 5.25pm, adding a further 327k (2.1%) on ITV1 +1.
Primeval's fifth run has already aired on Watch - averaging around 500k - as part of a co-production deal between ITV and UKTV following its initial cancellation in 2009.
Meanwhile, the franchise will continue exclusively on the digital channel with spinoff New World.
You've Been Framed followed on ITV with 2.11m (13.5%) at 6.30pm (+1: 295k/1.7%), then 2.61m (14.7%) watched The Cube at 7.30pm (+1: 160k/0.8%), and TV's Biggest Blockbusters rounded off a quiet night with 2.03m (10.2%) from 8.30pm (+1: 102k/0.6%).
BBC One fared much better with its Indiana Jones film, The Last Crusade (4.1m/24.5%) kicking off the evening at 6.30pm, after which Casualty grabbed 4.39m (21.6%), and a repeat of Mrs Brown's Boys amused 3.74m (22.2%) at 10.30pm.
Doc Martin gave ITV3 a boost with 1.12m (6%) from 8pm, ranking as the day's most-watched multichannel show.
CSI: Miami was Channel 5's best-rated broadcast with 1.22m (7%) at 10pm, higher than Big Brother's 886k (4.4%) in the 9pm hour and 125k (0.7%) on timeshift.
BBC Two failed to surpass a million viewers all evening, with its screening of The Hollow Crown only managing 670k (3.4%).
Overall, BBC One led a one-horse race with 23.3%, while ITV1 had 11.5% (+1: 1%). Channel 4 finished third with 6.7% (+1: 1%), ITV3 slotted in at fourth with 4.9%, Channel 5 had 4.2% (+1: 0.3%) in fifth, and BBC Two was last with 4.1%.
BARB ratings data supplied by Attentional