Alfie's discovery was seen by 9.03m (40.5%) on BBC One, and 988k (5.1%) on BBC Three.
EastEnders was the most-watched terrestrial and best-rated multichannel programme of the day, logging its best figures since April.
Elsewhere last night, a Holly-centred episode of Emmerdale also rated well, with 6.94m (33.9%) for ITV1 at 7pm.
BBC One's medical serials performed solidly: Holby City fetched 5.71m (24.4%) for an instalment titled 'Revelations', and Doctors - 'The No Man' - appealed to 1.58m (21.9%).
Over on Five, Ringo's stag night on Neighbours brought in 739k (10.2%) at 1.45pm, and 1.18m (8.5%) at 5.30pm, while Home and Away took 349k (5.1%) at 2.15pm, and 899k (5.4%) at 6pm. Fiver's first look logged 498k (2.6%).
BARB ratings data supplied by Attentional