It's the sort of image of "the future" many of us dreamed of when we were growing up watching Thunderbirds and The Jetsons, and a Bristol company is behind what looks set to be a flashy new home improvement craze.

Costing the best part of £50,000, the Cardok underground garage may not be cheap, but if you're a two-car family, with space on your drive for just one vehicle, it could be the difference between having to move home or being able to stay put.

Even in the current recession, business is booming for the Bristol company. A steady stream of wealthy customers are making the journey from London to visit the company's demonstration unit on Oakfield Road in Clifton.

"Most of our customers are fairly wealthy, and the recession doesn't seem to have hit them yet," said Alastair Soper, managing director of the company.

"In fact, it might be that people are thinking twice about moving home, and shaping their existing home to meet their needs.

"We only started the business two years ago, and we already have eight units in the ground, four in production and 10 currently in the planning stage. We also have 20 names on our waiting list, which means we have plenty of work throughout the next few months."

The Cardok is a pneumatic lift, worked by remote control, which can accommodate one car below the ground and one above it.

"Everyone loves them," Alastair said. "This particular unit has been in the ground for more than a year, and it's still turning heads every time we use it. People actually stop their cars to watch us parking."

Costing £48,000, plus VAT and installation, the Cardok may not be within everyone's budget, but Alastair says it's not as expensive as you might think: "If you live somewhere like Clifton for example, you can pay £90,000-£100,000 for a garage, if not more.

"If you own a million-pound house, but don't have enough space for two cars, then you can see why people would invest in it. After all, it is something that is likely to add value to your home.

"It's also considerably more secure than a traditional garage. Once your car is under the ground, nobody will be able to break into it or vandalise it."

Alastair's business partner, computer software engineer Alastair Newing came up with the idea because he was tired of having his car vandalised outside his Redland home.

"People had proposed the basic concept in America back in the 1920s, but it had never been built," Alastair said. "So we spent a couple of years developing a working model, before launching the business back in 2006.

"However, the idea seems to have really taken off in recent months. The orders are flowing in steadily."

The units need planning permission, but Alastair says they've never had any problem obtaining it from local authorities.

"Councils all seem to love the idea, because it's helping to solve the problem created by having too many cars parked on residential streets.

"It's also completely out of sight for most of the time – it's only when you raise the Cardok to park that you would actually know it's there."

The lift, which takes 10 weeks to construct and about three days to install, operates silently – so it won't concern neighbours.

"We've also designed it to be environmentally friendly," he said. "There's a growing issue about the amount of excess water that's running off our front gardens because they've been paved over to accommodate our cars. So we designed the Cardok so that it would collect all the rainwater that falls on it into a reservoir, which you could then use to water your garden."

Each unit has its own electricity generator, which can be used in the event of a power cut, and Cardok has done a deal with Stannah – the stairlift people – to ensure that if anything does go wrong, customers can rely on Stannah's 24-hour engineer call-out service.

"It also goes down well with insurance companies," Alastair said. "One man with a Bentley had been charged an annual premium of more than £5,000 when he parked his car in a well-to-do street in London, but that fell to £1,500 when he installed the Cardok."

The company is now designing a double-sized model, which could accommodate four vehicles – two below the ground and two on top.

"It's revolutionary, but it's a really simple idea," Alastair said. "It's exactly the sort of idea that could take off in the next few years."

For more information, visit www.cardok.co.uk or call Alastair on 0117 315 8560.