U.K. TV giant ITV’s flagship network on Monday night drew 7.5 million viewers with the 9 p.m. season 3 debut of hit series Broadchurch and averaged an audience of 2.9 million for the first edition of 10 p.m. experiment The Nightly Show , Britain’s answer to U.S. late-night shows. Broadchurch , starring David Tennant and Olivia Colman, became a U.K. ratings hit in its first season.