Not only does BBC Knowledge claim to be in the vanguard of broadcasting innovation, it ambitiously aims to change the way we learn. Programmes backed up by websites, information telephone lines, and fax-back services will be targeted not just at schools, but at the population as a whole.

The effect will be similar to that of the experimental revision series GCSE Bitesize, which transmits in the early hours on BBC2 - programmes which research published in last week’s TES suggests produce significant improvements in GCSE results.

However, the success of BBC Knowledge will depend on the audience having all the right technology, such as access to the Internet. At present, only between 5 and 10 per cent of homes do, although the numbers are rising steadily.

Existing educational output will be unaffected by the new channel. BBC Education and Channel 4 Learning are the key educational broadcasters in the UK, turning out around 30 hours of specially-commissioned programmes per week between them.

For schools this means cheap, curriculum-led, non-interactive television suited to whole-class teaching. BBC Knowledge has its sights set on bigger things.

To beef up its viewing figures, and ensure greater return on its colossal investment in digital programming, the BBC is pitching Knowledge at the entire population. The main targets are young children, who will watch the literacy and numeracy programmes at home, possibly with their parents; GCSE students working towards exams, and vocational and adult learners who want to learn new skills - a language or business studies, say - in their own time.

However, the announcement comes at a time when viewing figures suggest that the public is not interested in digital television. Of the 23 million homes in the UK, currently fewer than five million have satellite, with three million taking cable it could be a gamble.

Audience apathy was one of the main reasons why Channel 4 withdrew its bid to run a government-backed digital education channel. It did not believe that there was a strong enough market but the BBC is still in the running, along with two other commercial broadcasters. A decision is expected shortly.

The risk for the BBC is that by the end of the year it may have two dedicated education channels with no guarantee of an audience for either of them.

BBC Knowledge goes on air on June 1, and will be available free to anyone who has digital and cable television.