BBC baking competition The Great British Bake Off drew its highest overnight ratings ever with the final episode of its sixth season on Wednesday night and became the most-watched program of 2015 in the U.K.

The episode averaged 13.4 million viewers, according to overnight data released on Thursday. That amounted to a share of 54.8 percent of people watching TV in Britain at the time. The audience peaked with 14.5 million viewers. Observers said that tops all other overnight ratings  in Britain this year.

The launch episode of the sixth season, which was the show's second on the U.K. public broadcaster's flagship network BBC One, had reached an average audience of 9.3 million, making it the show's best-ever season debut.

The show's ratings have outperformed last season's. So far, the season-five finale had been the show's highest-rated episode ever in overnights data, with an average audience of 12.3 million.

"Baked and off! #GBBO final watched by extraordinary 13.4m/54.8% overnights audience," tweeted on Thursday.

The show features amateur bakers whose work is judged by experts. It has been credited with boosting interest in baking across the U.K.