The equivalent episode from the last series, which aired at 10pm on Thursday, July 31, 2008, was seen by 3.1m (14.8%), representing a decline of 29% year-on-year.
Earlier on Channel 4, The Home Show drew 1.58m (7.8%) at 8pm, then 1.77m (7.6%) tuned in for the first in a three-part series, How The Other Half Live, during the 9pm hour.
As Seen On TV put in 2.46m (12.7%) for BBC One between 8pm and 8.30pm. The audience then fell to 2.26m (10.7%) during The Rat Pack, while the 9pm screening of New Tricks logged a respectable 6.91m (29.6%).
Over on BBC Two, Rick Stein's Far Eastern Odyssey managed 2.57m (12.7%) at 8pm. Mock The Week and Never Mind The Buzzcocks drew 2.16m (9.3%) and 1.86m (7.9%) respectively in the 9pm hour, then Psychoville bowed out to 1.26m (6.2%).
Five documentary Blackbeard's Last Stand - Revealed interested 1.01m (5%) at 8pm, then 1.57m (6.7%) tuned in for The Mentalist during the 9pm hour.
ITV1's The Bill averaged 4.16m (17.8%) at 9pm.
Overall, BBC One came top during primetime with an average share of 23.4% to ITV1's 21.7%. BBC Two was third with 8.7%, followed by Channel 4 with 7.8% (+1: 0.8%) and Five's 5.3%.
Elsewhere, BBC Three's Sex: My Big Decision put in 296k (1.4%) at 9pm, and 424k (2.5%) tuned in for the penultimate episode of Lie To Me on Sky1 at 10pm.
BARB ratings data supplied by Attentional