Ratings for pay television service Foxtel have sunk over summer, a period ­dominated by free-to-air broadcasts of cricket and tennis.

Foxtel, which is a joint venture between News Corp Australia and Telstra, is suffering it’s worst average prime time audience for the summer period since 2005 to 2006.

Foxtel’s average total metropolitan audience in December and January fell 14 per cent to 682,000 from 6pm to 10:30pm, compared with last year.

From 6am to midnight ratings were down 10 per cent over the same period.

Foxtel lost the broadcast rights for the Big Bash League cricket competition, which had been one of its best ­rating programs, to free-to-air broadcaster Ten Network Holdings last year.