THE used car buying revolution continues at a fast pace, with another leading super-retailer predicting a dramatic shift towards downsizing.

Car supermarket group Motorpoint's latest survey shows that more than two-thirds of UK car buyers say they will be downsizing with their next purchase.

The firm says buyers simply want to save on escalating running costs.

Motorpoint's survey shows that drivers are concerned about more than just the soaring price of fuel - another benefit of choosing a smaller set of wheels is slower depreciation, which will improve even further as demand increases.

Owners of cars with lower carbon emissions will save money on road tax, too.

Motorpoint's managing director David Shelton said: "These figures show a potentially massive shift of over two-thirds of the motoring population - about 20 million people - into smaller vehicles.

"The increased demand for smaller cars is something that we are seeing from our customers right now.

"It's clear that the benefits of a smaller car are becoming more important, as a whole range of economic and environmental considerations start to bite."

Meanwhile, trade price guide publisher EurotaxGlass's says there is a marked decline of the upper-medium used car segment of the UK market.

The firm says new car registrations in this sector, which includes models such as the Ford Mondeo and Citroën C5, have declined by 48 per cent since the start of the decade.

In 2007, just 171,000 units were sold, signalling the lowest point in recent history for these previously popular cars.

In the used car market, a reduction in supply can often lead to a consolidation of values, but this has not been the case for the Mondeo and its rivals, according to the publisher of Glass's Guide to Car Values.

Managing editor Adrian Rushmore says these vehicles are increasingly overlooked because customers are opting to downsize as successive generations of vehicles have got bigger. This has led to a migration from upper-medium cars to either lower-mediums - the Ford Focus and Vauxhall Astra, for example - or to the now-commonplace compact MPVs, such as the Renault Scenic.

"These two groups of cars offer sufficient space, specification, and refinement for the majority of family-car buyers, and they typically cost less to purchase and to run than their larger siblings."

Mr Rushmore said that despite ongoing investment in developing their products in the segment, manufacturers were unlikely to be able to reverse the fall in sales.

"And he does not foresee any significant strengthening in second-hand values.

"Manufacturers, though, still have faith in this sector, as demonstrated by the proliferation of recent new model launches," he says.

"The last 12 months have seen the introduction of a new Mondeo, Renault Laguna, Mazda6 and Citroën C5.

"But, in spite of the reduction in used car supply, values remain in the doldrums.

"While these new products may bring a short-term revival in sales and residual values, the outlook is less than rosy."

Mr Rushmore said that in order to get your road tax down to the new 2010 zero, or under £95, rates, you have no choice but to drive a small car.