The Crimson Field dropped 700,000 viewers from last week's opener on Sunday (April 13), overnight data reveals.
The BBC One period drama was still the second most-watched show overall, attracting 5.4 million (23.0%) at 9pm.
Countryfile remained on top with 5.8m (28.7%) at 7pm, followed by Antiques Roadshow with 5.2m (22.5%) at 8pm. Match of the Day 2 scored 2.7m (19.1%) at 10.35pm.
On ITV, Endeavour dipped by around 400k from last week to 4.7m (20.0%) at 8pm (405k/1.9% on +1). Earlier, Catchphrase puzzled 3.5m (18.7%) at 6.45pm (246k/1.1%). Off Their Rockers tickled 3.8m (18.1%) at 8pm (248k/1.1%), while coverage of the 2014 Olivier Awards interested 722k (5.8%) at 10.35pm.
BBC Two's coverage of the 2014 Golf Masters attracted an average of 1.8m (9.6%) from 6.30pm.
On Channel 4, Richard E Grant's Dirty Weekenders appealed to 820k (3.5%) at 8pm (226k/1.0%). Movie The Three Musketeers thrilled 1.3m (6.3%) at 9pm (158k/1.2%).
On Channel 5, Spider-Man 3 entertained 1.2m (6.0%) at 6.30pm (137k/0.6%), followed by Grown Ups with 1.4m (6.8%) at 9pm (195k/1.4%).
BBC Three's broadcast of Toy Story 2 was seen by 804k (3.4%) at 8pm.
