Leading article: There are too many blots on our rural landscapes

Welcome to Britain in 2035. The future of our green and pleasant land sketched out by the Campaign to Protect Rural England is a true dystopia. Its new report conjures up a nation almost entirely covered by retail parks, meandering housing estates and endless ring roads. The famous English countryside has all but disappeared under a tide of concrete.

This is alarmist stuff, but there is little in the CPRE's report that is not already documented. The decline in Britain's farmland birds in recent decades has been highlighted many times, not least by this newspaper. The number of tree sparrows, corn buntings, turtle doves and skylarks has fallen steadily. And recently it was revealed that one in five of our wildflowers is threatened with extinction. The countryside is shrinking with, as the CPRE points out, 21 square miles lost to development every year. Fewer people than ever work on the land. An estimated 81,500 farmers and farm workers left between 1995 and 2004. There is more light pollution than ever. And all these trends are likely to get worse.

It is well known what lies behind this process. Building schemes are encroaching on green spaces as the areas around our cities are transformed into suburbs. Britain's airports are expanding. So is the road network. The decline in farming and the perverse incentives of the Common Agricultural Policy are leading to more polarised land management. Increasingly, the countryside is either intensely farmed or handed over to developers. And then there is climate change, which is upsetting the balance of our natural environment in unpredictable ways. According to the CPRE, 60 per cent of the English landscape has changed in ways that are "inconsistent with the traditional character" since the 1980s.

The countryside has changed over history, and its evolution will continue. But what sort of rural landscape do we want? The CPRE is by definition a conservative group, but the importance of this report is that it considers the long-term implication of the trends taking place. If such degradation were to happen overnight, there would be popular outrage. But since it is occurring in a piecemeal and gradual fashion, it goes largely ignored.

The CPRE's suggestions of what ought to be done to avoid this trend are, on the whole, sensible. Developers should be forced to use land efficiently and to build on brownfield land where possible. Businesses should be encouraged to procure food and commodities locally to reduce dependence on motorways. Farmers - who have not always been the best custodians of their land - should adopt a more proactive role in conserving and maintaining the countryside. Serious questions also need to be asked about our expansion of air traffic.

By far the most contentious issue regarding the countryside is house building. The Government hopes to build half a million new homes in the South-east in the next few years. This has been approved by the South East England development authority, although there is a challenge from environmental groups. The prime concern of development authorities is always going to be encouraging economic growth, rather than safeguarding the quality of the environment. And growth is by no means an ignoble objective. It is right, for instance, that homes should be provided for those priced out of the London market. But there is a danger that overdevelopment - particularly in the South-east - could increase the risk of flooding and threaten local wildlife.

There must always be a balance between economic growth and the health of the environment. As this report shows, we have been failing to find that balance for too long. It is imperative we rediscover it before it is too late and our treasured countryside disappears.