'I AM the Richard Rogers of chairs,' says Victor Lewis-Smith. The writer and radio producer is seated in his home-studio in York, demonstrating the hi-tech capabilities of his new electro-hydraulic office chair. 'I wanted the guts of the thing to hang out, like they do in the Lloyd's building or the Pompidou Centre - or, come to think of it, like my own do.'

The chair is unlike other chairs. For one thing it is a massive device, designed to take the full 13-stone impact of Lewis- Smith's generous and restless frame. For another, it is crammed with battery boxes, hydraulic pumps and cylinders, levers, buttons, cogs and hoses. It looks like a cross between one of those orthopaedic car seats that Volvo uses to test-crash dummy humans into concrete walls, the macabre latex creature designed by H R Giger for the film Alien, and an ejector seat from an inter-galactic space-fighter.

'That's the child in me,' says Lewis- Smith, 'a sad case of a boy who never grew up. I always wanted to be General Jumbo, the child general in the Beano who commanded all those miniature radio-controlled soldiers, planes and tanks from a gadget on his wrist. But the chair is more than a fantasy, it's actually very practical. I work up to 18 hours a day here, so I wanted a chair that stayed comfortable for long stretches, one that would turn into a bed at the touch of a lever so I could catch up on some sleep between bouts of work.'

Lewis-Smith is well known for his comedy programmes (The Mix goes out on Radio 5 at 10.10pm on Mondays), but his chair, although offbeat, is something he takes seriously. 'It's been designed so that I can move around easily in the studio without doing my back in. I originally wanted a seat as soft as feathers, but I realised that only a really firm chair can support your back for any length of time. This chair supports the spine at any angle. It's not quite perfect yet; I want to add speakers into the headrest.'

The Lewis-Smith chair is a one-off. The materials alone cost pounds 1,600; labour was free. It was a joint design venture between Lewis-Smith, acting as creative client, and Daniel Burnett, a newly qualified graduate from Newcastle Polytechnic's three-dimensional design course.

'I know Daniel through his father, an old BBC colleague,' says Lewis-Smith. 'Daniel had made this remote-controlled lamp out of bits of old sewing-machines and cars and I was very impressed. So we sat down together and planned out the chair. My office chair had just collapsed under me; Daniel needed a design project for his final year at college - and that's how the whole thing came about.'

'Because it was a college project,' says Burnett, 'the labour came free; but if Victor had had to pay for my time, the chair would have cost about pounds 18,000. I was offered pounds 10,000 for it, before it was completed, by a firm that specialises in making flight simulators.'

Burnett needed a seat with which to experiment before investing hundreds of hours in the real thing. He approached the Sunderland base of Nissan, the Japanese car manufacturer. Nissan was only too keen to help. The car seat it provided was used to test the hydraulic systems destined for the Lewis-Smith chair, and to help find the right relationship between seat, back rest and head rest.

While Lewis-Smith worked on his TV Hell special for BBC 2 (a compilation of the worst television clips of the past 60 years, scheduled for broadcast on 31 August) and wrote off his old swivel chair, Burnett slaved on the new one. It was completed just in time for his final-year college assessment; it then went on display at The Young Designers show at the Business Design Centre in Islington, north London, last month, and attracted considerable interest from Japanese visitors.

Now that the chair has been in action for a week or so, Lewis-Smith and Burnett have different feelings about it. Lewis- Smith feels its chunky design and engineering is well suited to his physique and way of working, while Burnett would like to make a much lighter version.

'I jumped in at the deep end when I started work on it,' he says. 'It really is a heavyweight. Victor likes that; he finds it reassuring. It's certainly very comfortable and he won't get backache - did you know that 33 million working days are lost in Britain each year through bad backs?

'But I know now that I could have used micro-hydraulic systems to make the chair lighter and less bulky. If I made a production model, it would probably be gas- powered. I'd abandon the hydraulics. They're very powerful and give tremendous lift, but they need a lot of energy.' So much so that the pair of chunky batteries hidden under the seat require recharging every week.

Lewis-Smith, however, is as happy as General Jumbo with his electro-hydraulic chair. He works in something of a creative heap, his study crammed with old and new bits of broadcasting technology. 'I particularly like the old three-lensed BBC TV camera I have as a giant desk ornament. I like the let-it-all-hang-out look of that generation of technology and that's, I suppose, why the chair is as it is.

'It's certainly a lot more solid than the last chair I had which collapsed with me on top of it. Still, as it was light, there was no damage done. If this one collapses it will go straight through the floor, taking me and everyone else with it.'

Making the most of a flexible friend

Hydraulic lever 1 raises and lowers the chair by up to 1ft. Useful if I'm losing an argument on the phone. A 6in lift usually allows me to regain the moral high ground.

Hydraulic lever 2 flattens the chair into horizontal mode. Useful for

sleeping or, alternatively, for informal appendectomy.

Hydraulic lever 3 tilts the chair sharply forward, like a post- modernist ducking stool. Useful for retaining balance during small seismic tremors or after imbibing too much British sherry.

Hydraulic lever 4 tilts head forwards and backwards for easy access to British sherry.

The levers also work in chordal combinations, permitting all manner of bodily contortions, and allowing the operator to perform advanced hatha yoga positions without leaving the chair.

Since use of lever 2 converts the chair into a bed, I have had no need to leave it for some time and can control all my bodily movements with one finger. Passers-by have started giving me sympathetic glances, so to avoid confusion I have purchased a 'Disabled' sticker, cut off the first syllable and stuck it on my forehead.

Victor Lewis-Smith

(Photographs omitted)