BBC1 thriller Undercover shed 1 million viewers on its second outing on Sunday night.
The drama, a rarity for UK primetime featuring two black actors as leads, drew an average audience of 4.2 million and an 18.7% share of total TV viewing between 9pm and 10pm on Sunday.
The first episode of the six-part drama, which stars Sophie Okonedo and Adrian Lester, drew 5.2 million viewers and a 24% share.
The drama lost out to Home Fires, ITV’s world war two drama, which drew 4.7 million viewers and a 21.3% share of total viewing between 9pm and 10.05pm.
However, Home Fires also lost audience week on week, having debuted with 5.2 million.
The biggest drama of the night was The Durrells, starring Keeley Hawes and based on the memoirs of Gerald Durrell, which drew 5.9 million viewers and a 24.9% share between 8pm and 9pm.
Viewing of the Durrells was down 500,000 on the 6.4 million (29% share) who tuned in to the first episode of the six-part series.
