Autumn Property Survey: Talking 'bout regeneration: Builders are abandoning greenfield sites for the inner cities, says David Lawson

If every encroachment into the countryside in England since the war was lumped together, not one blade of this grass in the south-east would have escaped a blanket of concrete.

But there is more to come. Over the next 15 years enough new homes are needed in this region to create a city the size of Birmingham, so the pastures suddenly appear even more threatened.

But there is an alternative. More than 40 per cent of development already takes place on cleared land within towns, but vast numbers of buildings stand empty or derelict which could also be turned into homes. Not all jump to mind as typical living space, however.

Deep in the heart of London's Docklands, for instance, a derelict fire station that played a vital role in fighting the Blitz has been transformed into 11 apartments. They were so popular that most sold before work was even finished.

'We wanted to keep what had become a local landmark,' says David Pretty of Barratt Homes, which inherited the hulk as part of the site for its acclaimed neo-classical Sovereign View development next door.

An even more spectacular building not far up the river at Rotherhithe is now entering its third life. Alaska Works is an architectural gem created by Thomas Wallis, more famous for his art nouveau Hoover and Firestone buildings created in the 1930s. It was for many years a fur factory before being remodelled into offices during the boom.

Despite a huge grant from the Government, however, the developer went bust.

Now it has been reborn as flats. Again the popularity of renovations came through. London Buildings, which specialises in turning commercial white elephants into homes, sold 40 on the day Alaska was relaunched.

One reason for this enthusiasm is that conversions are often cheaper than new homes. It often costs builders less to retain these hulks than to buy cleared sites and start afresh. Prices at the fire station, for instance, started at pounds 62,500, and were even lower in Alaska Works. London Buildings created a similar fashionable enclave north of the river at Bow after taking over the old Bryant Match Works.

In Salford, a street of neat, red-roofed houses on the Cheetham Estate looks freshly sprung from a builder's barrow. But locals know that beneath the surface are the remnants of concrete, flat-topped buildings which had been shunned even by the homeless.

Lovells, which is bringing around 200 homes back to life every year across the north of England, says it is often cheaper to renovate these old houses than demolish them. Most go to housing associations, but some provide the first cheap home for first-time buyers.

On the Southfarm estate in Sunderland, for instance, starting prices were kept down to as little as pounds 20,000.

Conversions are just as popular higher up the ladder, however. Farley Castle, near Wokingham in Berkshire, is a brick fantasy built at the turn of the 19th century as a country home. It, too, has been through various lives, first as a hotel and more recently a school before being taken over by FairBriar Homes.

The grounds were probably the main attraction to the builder, providing sites for almost 35 of the small new homes which are hard to find in this part of the world. But the house caught the imagination of locals. .

They had an inside view of the conversion of a listed building into three homes, each of which retains many original features such as high ceilings and galleried staircases. All were quickly snapped up for between pounds 255,000 and pounds 360,000.

Conversions of institutional buildings are likely to play a major part in relieving pressure on the countryside over the next few decade as worn-out property is given a new life. Old hospitals will be one of the richest sources as the health service adjusts to 'care in the community' and pressures to sell land and buildings.

Buyers in east London were offered a claim to fame under one scheme.

Wanstead Hospital became known to millions as St Swithin's during the 1970s Doctor television series. One wing is now being converted into eight flats - again by Barratt - at prices from pounds 75,000.

Inner-city offices and old factories are also being bought up for conversion. London Buildings is about to announce a new campaign for converting workshops, while more than 200 planning applications are being considered for switching empty London office blocks to flats.

Again, these are proving popular with buyers. Barratt sold two-thirds of the apartments planned for a Wapping office block within weeks of announcing the project, and has another on the starting blocks in the Barbican.

(Photographs omitted)