The average amount of television watched by UK viewers each day reached a new high of four hours and three minutes a day in the six months to the end of June.
That is an increase of 51 seconds a day, year-on-year, according to the survey by the television marketing body Thinkbox, and means that the average person will sit in front of the television for a total period of more than eight and a half years in the course of their lifetime.
Non-live "time-shifted" viewing through devices like Sky + now accounts for 9 per cent of television viewing. But many viewers are choosing to watch programmes such as The X Factor and The Apprentice "live", so that they can follow the debate on Twitter in real time without reading "spoilers" online.
Commercial channels are benefiting from time-shifting, with viewers exposed to an average of 47 adverts a day, up from 45 in the same period last year.
The average TV viewer watched 18 hours and 9 minutes of commercial television a week, an increase of 48 minutes a week on the same period last year.