Alex Epstein's exit from the show averaged 6.42m (24%) for BBC One in the 9pm hour, down 880k week-on-week.
The programme was hit by coverage of The Pride Of Britain Awards 2010, which pulled in 6.23m (24.7%) on ITV1 between 8pm and 10pm, while 105k (0.4%) watched in HD.
Prior to the awards, special tribute programme Farewell Jack appealed to 6.9m (30.7%) from 7.30pm and 120k (0.5%) in HD.
Earlier, The One Show grabbed 4.48m (20.4%) on BBC One from 7.30pm, before new series Wallace & Gromit's World Of Inventions continued to 3.63m (16.2%), down by more than 2m week-on-week.
Jimmy's Food Factory and Nigel Slater's Simple Suppers cooked up respective audiences of 3.25m (14%) and 3.1m (12.7%) on BBC One from 8pm. A mid-week edition of Match of the Day entertained 2.75m (25.5%) from 10.45pm.
Channel 4's Celebrity Coach Trip continued to 1.94m from 5.30pm, while 306k (1.4%) watched on timeshift. Later, Animal House grabbed 880k (3.7%) from 8pm and 87k (0.3%) on Channel 4 +1.
Grand Designs dropped to a series low of 1.67m (6.3%) on Channel 4 in the 9pm hour and 217k (1.1%) on timeshift, before Rude Tube: Rude Tunes amused 1.29m (7%) and 127k (1.4%) an hour later.
Over at BBC Two, Escape To The Country took 1.68m (7.6%) in the 7pm hour, before Edwardian Farm captivated 2.53m (10.6%). Ancient Worlds then educated 1.73m (6.5%) in the 9pm hour.
After The Apprentice, spinoff show The Apprentice: You're Fired! pulled in 2.55m (11.8%) on BBC Two from 10pm.
Channel Five's Highland Emergency attracted 575k (2.6%) from 7.30pm. It was followed by Battle Of Arnhem: Tour of Duty, which brought in 527k (2.2%). NCIS and Law & Order: Criminal Intent then secured respective audiences of 758k (2.8%) and 970k (5%) from 10pm.
Overall, ITV1 owned primetime with 23.9% (HD: 0.5%) against BBC One's 19.1%. BBC Two came in third with 8.5%, followed by Channel 4 with 5.1% (+1: 0.6%) and Channel Five with 2.8%.
Elsewhere, the biggest multichannel audience of the night went to The Only Way Is Essex, which had 661k (3.5%) on ITV2 in the 10pm hour and 101k (1%) on timeshift.
BARB ratings data supplied by Attentional