Ratings for the BBC's flagship analogue TV channel have hit an all-time low as the digital sector continues to make gains.

According to viewing figures from industry body BARB (Broadcasters' Audience Research Board), BBC1's audience share was just 22.2% last week, the lowest ever for the station.

The news is a fresh blow for the publicly funded broadcaster as it tries to define its role in an age of unprecedented media choice. Its operations are currently the subject of a government review ahead of the renewal of its Royal Charter in 2006.

BBC1 faces growing competition from the wide range of channels offered by digital television, access to which is rising rapidly.

The so-called multichannel sector (an amalgam of all channels bar the five traditional analogue terrestrial stations) pulled in 27.7% of the audience, higher than both BBC1 and the leading commercial operator ITV1, which took a 22.9% share.

Of the other analogue terrestrial channels, BBC2 attracted 10.2% of viewers last week, Channel 4 took 9.7% and Five pulled in 7.3%.

Despite its poor ratings, the BBC defended its flagship's output. "BBC1 has had a week with a great depth and breadth of programmes across all genres," it declared. "You would not be able to find [similar shows] elsewhere in the schedule."

Data sourced from: MediaGuardian.co.uk; additional content by WARC staff