Viewers who tuned into the launch of Jamaica Inn were left frustrated after struggling to make out the dialogue in the BBC's new period drama.

The first instalment of the TV adaptation of Daphne du Maurier's classic gothic novel, starring Downton Abbey actor Jessica Brown Findlay, was broadcast on BBC1 on Monday.

Viewers complained that they had to switch on the subtitles or turn up the volume to the maximum setting to understand what the cast was saying.