BBC1 thriller Line of Duty was the big ratings winner on Sunday night, although the return of ITV's The Durrells was also extremely popular
The Thandie Newton-starring police drama averaged an audience of 6.6 million, while James Norton’s return attracted an average of 4.4 million.
The two shows went head to head in the 9pm slot and, even at its peak of 4.7 million viewers, Grantchester still had a two million shortfall against its rival.
Line of Duty has seen its weekly audience grow steadily since the show moved to BBC1 in March. Previous series have screened on BBC2.
Sunday night’s other new addition, The Durrells, returned to ITV at 8pm with an audience of 5.5 million viewers, peaking at 5.9 million.
The ITV drama is based on British naturalist Gerard Durrell’s autobiographical books such as My Family And Other Animals, which document his childhood growing up on the Greek island of Corfu.
Keeley Hawes returned as Louisa, a widowed mother who moves her family to the island in the 1930s, for the second series.
The figures for ITV include viewers of the ITV+1 and ITV HD channels.
The drama went head to head with the final episode of Top Gear in the 8pm time slot.
BBC2’s motoring programme peaked with an audience of 2.1 million and enjoyed an average of 1.9 million viewers.
Viewers credited former Friends star Matt LeBlanc with ‘saving’ the show as it came to a high-octane end with an episode that featured boat racing and nude ramblers.
Matt returned to host the revamped series with Chris Harris and Rory Reid as co-hosts, following Chris Evans’ departure last year.
Other weekend viewing highlights included a massive 9.2 million audience for the second episode of Britain’s Got Talent on Saturday night.