Lewis was Friday's (October 10) highest-rated show outside of soaps.
The new series of the ITV drama was seen by an average audience of 5.28 million (24.9%) from 9pm. A further 279k (1.7%) watched it an hour later on ITV+1.
Earlier on in the evening, Gino's Italian Escape: A Taste of the Sun was viewed by 2.65 million (12.7%) at 8pm on ITV.
Have I Got News for You was once again BBC One's highest-rated show outside of soaps, scoring viewing figures of 4.14 million (19%).
BBC One's evening began with 3.48 million (18.6%) for The One Show at 7pm, while 2.89 million (14.5%) tuned in to watch A Question of Sport immediately after.
The evening continued with 3.35 million (15.6%) for Would I Lie to You? 8.30pm, while the final episode of Big School attracted 2.37 million (11.4%) at 9.30pm.
With guests including John Cleese and Taylor Swift, The Graham Norton Show rounded off the evening with 3.17 million (24.7%) at 10.35pm.
Over on BBC Two, The Great British Bake Off Masterclass picked up an average of 1.7 million (8.8%) viewers at 7pm, followed by an evening high of 2.41 million (11.6%) for Mastermind at 8pm.
Elsewhere, Lorraine Pascale: How to Be a Better Cook informed 1.49 million (7%) viewers at 8.30pm, Tom Kerridge's Best Ever Dishes continued with 1.15 million (5.3%) at 9pm, while Gardeners' World played to 1.61 million (7.8%) at 9.30pm.
QI was seen by a slightly reduced audience of 1.81 million (10.1%) at 10pm.
Channel 4's evening began with 470k (2.2%) for Stars at Your Service at 8pm, followed by 2.64 million (12.4%) for Gogglebox immediately after.
Alan Carr: Chatty Man, which featured guests Hugh Grant, Davina McCall and Noel Fielding, entertained an increased audience of 1.23 million (7.7%) at 10pm.
Paul Merton: World's Biggest Cruise Ship was Channel 5's highest-rated show with 815k (3.9%), beating the likes of JFK's Secret Killer: The Evidence with 499k (2.3%) and Body of Proof with 591 (3.6%).
BBC Three's Family Guy was among the most popular multichannel shows. The third of four episodes peaked with 500k (8.8%).
