Merlin, which features newcomer Colin Morgan in the title role, came second in its slot with 5.3 million viewers for a double bill behind Fox’s repeats of cartoons Family Guy and American Dad.

The drama was due to air between 8pm and 10pm, but started 10 minutes late because of an overun from the US Open golf tournament.

ABC also aired an imported series, German-made drama Impact, about a meteor attack, which pulled in 4.8 million between 9pm and 11pm.

However, US trade title Variety was not impressed with the ratings for either Merlin or Impact, describing them as “scrawny”.