The word of mouth clearly is that this new technology is baffling and fiddly

Only flying an aeroplane, using a sewing machine and riding a motorbike are seen as more difficult.

This worries Patricia Hodgson, chief executive of the ITC.

Last week she organised a one-day seminar, along with the Design Council and the Consumers' Association, aimed at persuading broadcasters and receiver manufacturers to think harder about "usability".

"If we don't offer services and equipment that are user-friendly," she told the seminar, "people will not come to them."

And that is bad news not just for service providers and set manufacturers but for the government, with its target of converting us all to digital TV by 2006 or 2010.

Baffling

Hodgson thinks one of the main reasons why digital take-up looks like plateauing at around 50% penetration is that the technology is widely seen as too complicated.

Perception of course is not the same as reality. With digital penetration now at around 33%, some two-thirds of the ITC/Goldsmith sample of 1,000 consumers would not have had a set.

But they have heard about digital and interactive TV, and the word of mouth clearly is that this new technology is baffling and fiddly.

People expect TV to be fast and entertaining

For many people that is clearly the reality as well - especially if they are among that growing tranche of the population which is over-55 and suffering from declining physical and mental powers.

Prof Alan Newell of Dundee University reckons too many computers, televisions, VCRs, websites and interactive TV services are designed by and for a very untypical user.

That is a young male who is highly dextrous, has good vision and memory, is besotted by technology, is more interested in playing with systems than using them and will go to extraordinary lengths to obtain a desired result.

Does that sound like your grandmother? I thought not.

The truth is of course that designing with older users in mind almost always produces devices which work better for younger users as well.

It sounds simple. In reality it is not so straightforward. Designing for simplicity can give rise to a different kind of complexity.

You want to present information on-screen in large, clear, easy-to-read text? Fine, but you will get fewer words on screen, which means more screens and more fiddly button-pressing between them.

Expectations

Also much of the complexity is a result of extra functionality. Designers have to find a way of giving users that want it access to all those added bells and whistles, while stopping them from confusing the majority for whom they are unnecessary.

Do not assume that what works in the environment of the PC and the internet will work in interactive TV

The message from the Design Council and from Serco, a specialist usability consultancy, is to design with the user in mind.

Involve the user in the design and testing process. Always bear users' expectations in mind.

Do not assume that what works in the environment of the PC and the internet will work in interactive television.

Remember that people expect TV to be fast and entertaining.

Lastly, we must beware laying all the problems of interactive TV and digital at the designer's door.

There are many reasons why some consumers have been slow to sign up for digital. One is that the services themselves are often disappointing, and do not live up to the hype.

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This column also appears in the BBC magazine Ariel