Gardening: United against the common enemy: Why did two environmentalists set up Common Ground? Anna Pavord lent an ear, then couldn't get it back

In the lane that ran past our first house, a brick-built cottage near Petworth, West Sussex, two enormous slabs of Sussex marble jammed with fossils led up to the churchyard on the opposite bank. The bank itself was rough, but covered with primroses in spring. There were even a few glow-worms.

All that disappeared one morning when a bulldozer arrived to carry out a road-widening scheme. Liszt's Piano Concerto in B minor, played fortissimo by Alfred Brendel, did not stop the bulldozer in its tracks, as I had imagined it would. Fortunately, Common Ground has developed effective ways of protecting what it calls 'local distinctiveness'.

Most conservationists work at saving rare things - whales, wild orchids and 15th-century wall paintings, for example. That is how Sue Clifford and Angela King, the two halves of Common Ground, met, fighting noisily for the strange and particular. 'Then, by the early Eighties, it was obvious that it was the ordinary things that were becoming rare,' Ms Clifford says. She is the one that does the talking - and, boy, can she talk. The name Common Ground suggests co-operative ventures, common sense, a combination of the practical and the philosophical. But what does it actually do? Even if you know its connections with parish maps, community orchards and apple days, it still remains elusive. This is deliberate, Ms Clifford says. 'If we remain diffuse, nobody can pigeonhole us. Once that happens you get forgotten.'

Common Ground relies on government and charitable funding, but is not primarily a spending organisation. It instigates projects (like Celebrating Local Distinctiveness, an information pack published this week) that reinforce local identity, making residents aware of how their patches in Devon or Dorset differ from those in Cumbria or Northumbria and suggesting ways to reinforce the differences.

Local building styles and materials - cob and thatch, granite and slate - used to be powerful ways of establishing a regional identity. No longer. Now 'Cotswold' stone, 'Welsh' slate and 'Sussex' tiles are widely available. The spread of big supermarkets has had the same effect, with tithe-barn Tescos and sub-Italian Safeways.

These complaints are frequently heard. Common Ground believes that doing something about them does not mean stopping the clock but simply demanding the best - accepting change, but not at the expense of the authentic patina that is built up through accumulation of detail.

When you try to explain their work to others, you end up sounding like a first-year sociology student. 'Particularity, based in nature on the foundations of geology and climate, has diverged with the alchemy of life, the articulation of the social and economic demands of successive societies . . .' The words slide seamlessly through the brain.

One of the first projects set up by Ms Clifford and Ms King involved a series of parish maps on which communities recorded important elements in their patch. Maps have been painted, woven, collaged and photographed in Muchelney, Penkridge, and Nassington. They contain field names, legends, elements of natural history, local landmarks, ponds and barns. The maps, displayed in village halls, provide a means to measure change.

More recently, Common Ground has been commissioning artists, including Andy Goldsworthy and Peter Randall Page, to create works that celebrate particular areas of landscape. If you walk the Dorset coastal path, you will find a Randall Page shell built into a dry stone wall on the Weld estate near Lulworth.

On the Isle of Portland, Dorset, is a more complex project, a land work by the sculptor John Maine that celebrates the area's tradition of quarrying. Five stone terraces, whose shapes echo the strip lynchets of the local landscape, snake across the landslip area where Chesil Bank ends. Maine has been working on this project for seven years and expects to complete it this year.

With pounds 25,000 awarded to it for communal art by the Prudential Assurance Company, Common Ground has been working with Randall Page again.

The most recent Randall Page sculptures can be found in Devon, one lying like a great seed on an island in a stream, another like the two halves of a brain split either side of a long avenue of beech trees, yet another like a rock with a spring bubbling through it. The works are strong and physical, drawing from and reflecting their surroundings.

Common Ground's work is full of paradox. How, for a start, can local distinctiveness be defined now that people are endlessly on the move and when the raison-d'etre of communities, mining villages and cotton towns disappears with the jobs? Ms Clifford and Ms King work from offices in Covent Garden. For several hundred years, local distinctiveness there meant fruit and vegetables. The Greater London Council brought that tradition to an end rather abruptly.

'The things that have been can still inform and enrich,' Ms Clifford says. 'The last barrow-maker has gone, but his name is still on the building, which is now a carpet shop. Change is happening here in a positive way. The dance goes on and when new people enter into it, it is revitalised, enhanced.'

What about areas where change is neither revitalising nor enhancing? What then? 'Look,' she says, 'we are all capable of taking the first steps. We can give courage by showing what is possible. Become a councillor. Write to your local paper. Express your feelings. We have to reinforce democracy at the local level. We have to show that small things are important.'

Yes, but, what happens when local distinctiveness makes its mark by way of fake bubble glass in bow- fronted stained-wood windows and stick-on facades of make-believe stone - the people's choice? 'We have to say we have a position on this,' Ms Clifford says. 'There are questions to be answered here of authenticity, appropriateness, quality. Stone cladding, stained-wood windows and bubble glass fail on all counts.'

After a while you tire of saying: 'Yes, but.' You are won over. You want to punch the air and cry simply: 'Yes, Yes, Yes]' Except perhaps to the tree dressing.

There is an artificial folksiness about Common Ground's attempt to revive a deep-rooted, ancient ceremony by decorating chosen trees at the nadir of the year. 'Every Tree Counts' say posters hanging from plane trees in Leicester Square; and all through the trees were hung huge, cut-out numbers. Such indigntiy. Too clever by half.

However much you test the patience of Ms King and Ms Clifford with your carping, the cracks never show. 'We can't be responsible for all the things that are going wrong with society. We just want to help people to build back into their lives some of the things that made them important. We have faced up to just some of the big questions and recognised that there are a lot of small answers.'

Common Ground, 41 Shelton Street, London WC2H 9HJ (071-379 3109).

(Photograph omitted)