Livestock at Manor Farm, Cholsey, is changing shape. Executives and other office workers will soon park their cars where cattle used to walk. For farmer Stephen Bitmead and his wife Penny have heeded Government calls to diversify, embarking on an ambitious programme to convert their historic barns into offices.

Across the lane from their mellow 18th century farmhouse is what at first sight appears to be a whole village of beautiful buildings, all with huge expanses of typical Berkshire-red roofs, Cholsey having been part of Berkshire until the 1974 county boundary changes.

Only slowly do you realise that all except two are barns, now rendered redundant by modern farming methods.

The reincarnation of one barn, an 18th century listed example, as two offices totalling 6000 sq ft, is now nearing completion. It is the first stage of a planned three-phase programme.

Only slowly too, do you realise that change is nothing new here. The monks of Reading Abbey owned the largest tithe barn in England, which stood on this site, until they were turned out during the Reformation in the 1540s.

Even in the 1970s one of the barns, now still standing, was listed in the Guinness Book of Records as being the longest barn in Britain. It stands near Cholsey parish church, which has Saxon origins.

But paradoxically enough, it is precisely because Mr and Mrs Bitmead want to achieve some sort of continuity, a link with the past, that they are converting the barn in a bid to preserve it for posterity.

Mr Bitmead said: "The question was whether we could go down the path of converting the barn for housing, or for commercial use. We decided on commercial, as it seemed to leave us with more control."

The Bitmeads are coy about their investment in the project, which they are tackling with the help of Dorset specialist in rural conversions Pineapple Developments, but admit to the sum being around the six figure mark.

They expect to house about 50 office workers in the converted building.

Mr Bitmead added: "I am the third generation to farm this land and I am keen not to be the last. My grandfather, originally a tenant farmer here, bought the farm almost 100 years ago.

"We reckon that converting the barn will both preserve it and enable us to hang on here. No longer appropriate for modern farm equipment, we believe a sympathetic conversion to offices is the best way of preserving a working building for future generations."

The listed Grade II barn now being transformed was built in the early 1700s, then added to throughout that century. It was originally used for threshing corn then, more recently, for storing potatoes grown on the 600-plus acre farm.

The Bitmeads used to run a mixed farm but now, like so many others in Oxfordshire, have gone over to arable only. Today there are only one third the number of dairy farms (118) left in Oxfordshire compared to a decade ago, and only a fifth the number of pig farms (177) according to the National Union of Farmers.

The conversion will result in many of the barn's historic features becoming more apparent. For instance the elm timbers, some still retaining the bark that was on the tree 300 years ago, will be exposed.

Mrs Bitmead said: "It will have the look and feel of an historic building, but with the necessary cabling infrastructure to meet modern office needs."

It was also an ideal opportunity to use environmentally friendly technology. Pumps using ground source energy will provide heating in winter and cooling in summer, while large windows will maximise natural light.

And what about the impact of such a development on the idyllic rural scene?

Mr Bitmead said that by and large the local community had been supportive, realising that the increased activity would bring more trade to the village of Cholsey.

The hope is that instead of commuters leaving every morning from Cholsey station, some might arrive there as well, and then cycle to the barn conversion.

Mr Bitmead said the enormous barn, built in the early 19th Century on the site of the mediaeval tithe barn belonging to the monks, forms no part of the present conversion programme.

He added: "However, there are two other barns which we plan to convert if this project goes the way we hope."

So the question remains: what are the other two buildings in the complex? They are farm workers' cottages.

Mrs Bitmead said: "Four generations of the Buckingham family, two members of which still work here, have lived at Manor Farm. Both their father and grandfather were born here, worked here, and died here."

Long may they continue to live there. But how different will the cottages seem when they have offices, not barns, as neighbours?

o Contact: Cholsey Great Barns, 01491 651119