Rescheduled due to the BBC's commitments to Euro 2012, the medical serial pulled in 4.76m (21%) for the conclusion of a two-part story, entitled 'All in a Day's Nightmare'.
EastEnders gave Casualty a leg-up by recording 6.77m (30.1%) at 8pm. BBC Three's repeat added 716k (3.4%), while 313k (7.6%) watched the omnibus from 12.15am.
Emmerdale was ITV1's only soap to air, grabbing 5.49m (27.4%) at 7pm and 255k (1.4%) an hour later on +1. Coronation Street's usual double bill was not screened because of ITV's football coverage.
Elsewhere, Hollyoaks nabbed 729k (3.7%) for Channel 4 at 6.30pm (+1: 162k/0.8%), after which E4's first look fetched 421k (2.1%) at 7pm.
Neighbours attracted 687k (3.1%) at 1.45pm and 620k (3.9%) at 5.30pm on Channel 5, while Home and Away took 550k (3%) and 344k (1.8%) for 5*'s first look.
Meanwhile, Doctors held 1.41m (17.5%) in the 1.45pm lunchtime slot it shares with Neighbours.
BARB ratings data supplied by Attentional