A national park authority yesterday unveiled radical plans to tackle a chronic shortage of affordable housing.

A national park authority yesterday unveiled radical plans to tackle a chronic shortage of affordable housing. It envisages discounted properties where public subsidies would be passed on to the next purchasers.

The shortage of affordable housing in the Cairngorms has led to an age imbalance, with the number of people aged 60-74 predicted to increase by 85% from 2001 to 2025, while the number under 39 is expected to drop by 30%.

Last year the authority mooted the highly controversial idea of residence qualifications, under which new houses could only be sold to people living and working in the park. They were rejected.

Providing affordable housing in the park, where some buyers are willing to pay up to £250,000 for a two-bedroom house, remains one of the authority's primary goals.

Its local plan, which goes out to public consultation today, identifies development needs over the next five years and estimates that 1030 new homes will be required, from housing association properties for social rent to expensive holiday homes.

At each locality the maximum capacity is identified so that over the long term, a balance of the type of housing can be achieved.

But the authority wants to go further. Where a developer is building two or more units, the authority would expect 50% to be affordable housing when there is public subsidy involved. This would include accommodation for rent, low-cost home ownership and serviced plots for self-build.

If there is no public subsidy the authority would expect any development of four or more houses to have 30% affordable housing.

The authority argues that affordable homes should not just be for rent. A number would be offered for sale at less than the market price to people who are unable to compete for houses.

The discount would be provided by the developer who would recoup the lost profit from the bigger properties for sale at higher prices.

If the house was sold on, the discount would be passed on to the next purchasers.

David Green, Cairngorms National Park convener, said: "Crucially, the local plan will also address the problem of the lack of housing, an issue which time and time again is cited as one of the main difficulties facing people living and working here. As well as providing more housing, it will ensure more people living in the park will be able to access and afford it."

David Sutherland, chairman of Tulloch Homes, one of the biggest builders in the north, gave the proposals a very cautious welcome.

"As the largest provider of affordable housing in the Highlands, we would find any innovative solution to assist greater provision to be welcome and interesting," he said. "However, any initiative which involves restricting market forces in such a localised market as the Spey Valley would require very serious evaluation."

James Jopling, head of campaigns at Shelter Scotland, said: "Most local authorities work to 25% of new housing being for affordable, but the park authority's idea of discounting properties in this way is in advance of anything I have heard of. It certainly is something that local authorities should examine to see if it could be applicable in their areas."

Last week, 60 derelict or disused properties were identified as candidates to provide more affordable housing in the park.

Their owners could receive up to a third of the costs of restoration if they agree to lease them for a fixed period.