Leslie Moonves, CBS chief executive, on Tuesday suggested that sexist attitudes were partly to blame for the faltering performance of Katie Couric, the news anchor he recruited to the network with a $15m annual pay package.

“I’m sort of surprised by the vitriol against her. The number of people who don’t want news from a woman was startling,” Mr Moonves said of the audience’s reaction to Ms Couric, who this month brought ratings for the CBS Evening News to a 20-year low.