The fourth episode of the talent contest averaged 10.46m (47%) for ITV1 between 8.20pm and 9.20pm, down from last week's series high of 12.24m (52.3%).
Spinoff show Britain's Got More Talent brought in 1.51m (8.2%) to ITV2 at 9.20pm, with a further 155k (1.1%) on timeshift.
Before Talent, sci-fi drama Primeval continued to put in decent numbers, with 4.67m (25.2%) tuning in from 7.20pm.
The latest episode of Robin Hood had a less impressive 3.47m (22.7%) for BBC One at 6.20pm, after which John Barrowman variety show Tonight's The Night appealed to 3.84m (21.6%).
The National Lottery - 1 vs 100 took 4.14m (19.6%) at 8.05pm and Casualty grabbed 5.15m (24.2%) at 9.10pm.
ITV1's screening of action sequel X2 appealed to 2.85m (17%) from 9.20pm.
Henry VIII's Lost Palaces: A Time Team Special interested 690k (3.3%) on Channel 4 from 7.45pm, then at 9.20pm, a screening of Dodgeball picked up 1.02m (5.5%).
Five's NCIS double bill brought in 921k (5%) and 1.07m (4.8%) from 7.25pm, then a new episode of CSI: NY notched up 1.79m (8.8%). Law & Order closed off prime with 1.23m (7.7%).
BBC Two's snooker coverage averaged 1.71m (8.7%) between 7pm and 10.30pm.
ITV1 led primetime with an overall share of 28.7% to BBC One's 20.4%. BBC Two was in third place with 8.8%, followed by Five with 6.3% and Channel 4 with 4.3% (+1: 0.4%).
Ratings data supplied by Attentional