Time travels: The Chiltern Open Air Museum takes rural buildings and restores them to working order. Jane Norrie became a medieval peasant for a day

It is not often you come across a museum where the exhibits are all buildings. But this is the case at the Chiltern Open Air Museum. Here, in a conservationists' paradise, buildings have been rescued for posterity. The 400- year-old Northolt Barn was repeatedly set alight by vandals, but now, in its resurrected state, it provides a peaceful store for hay.

On their original sites, the buildings have all been meticulously surveyed and photographed before being dismantled, repaired and re-erected at the museum. There, to recreate the original interiors, they are furnished with suitable artefacts, from agricultural machinery to ovens or toys.

The wonder is that, since the museum was set up as a charity in 1976, nearly all this has been accomplished by volunteers. The museum's emphasis on re-inventing the past has attracted an energetic group of Friends. Numbering more than 1,000, they have turned their hand to every task imaginable from serving teas to thatching.

Living history is the key. As a visitor you can wander along 'medieval' fields and browse round a Victorian farmyard. See how the farmers toiled to make hay; how cottagers baked bread and husbanded their livestock.

Forge, granary, shepherd's van, stable and byre. In a predominantly agricultural area, farm buildings predominate. But industrialisation is not neglected. A bright red telephone kiosk, a furniture factory, a 1930s prefab and even a loo signify the dubious march of progress.

Repairs and replacements, purists will be glad to know, are never disguised. The oldest building - and the only reconstruction - is the magnificent Iron Age House. Inside, as smoke from a central fire wafts up past you and you become aware of the early tools and skins on the floor, the atmosphere is spellbinding. Outside, the house is surrounded by a ditch and bank and within this enclosure plants are grown, including woad, flax, madder and medicinal herbs. Woad turns out to be a cabbage-like plant. And on the day of my visit it was being used by yet another volunteer to give demonstrations of dyeing.

This is what particularly appeals to me about the museum. It is not just recreating the past but recycling natural history. The wood for building the Iron Age House, for instance, was all taken from the museum grounds. In preparation for re-erecting its medieval buildings, the museum is currently carrying out experiments into wattle and daub. Daub is a mixture of mud, straw and dung - and, yes, the dung is provided by the museum's own cows. The 'medieval' fields are grown in rotation in the traditional way. Old varieties of seed are planted and the products again put to use: long straw for thatching and grain as feed for the hens. Shades of the good life.

Chiltern Open Air Museum, Chalfont St Giles, Bucks (0494 871117). Open to 30 Oct, Wed-Sun 2.00-6.00pm, pounds 3/ pounds 2.50

(Photograph omitted)