V isitors to the landmark 17th century post mill at Brill earlier this year will have been surprised to find it surrounded by scaffolding. The mill that stands in a commanding position on the village common, overlooking the surrounding the countryside, was undergoing the first stages of restoration.

Scaffolding will return later this year, when another round of repairs, costing around £130,000, begin. The two phases of renovation are the first to be carried out for about 15 years and then the work will be followed by a regular period of maintenance.

No-one knows the exact date the mill was built, mainly using oak trees cut from the Bernwood (or Bernwode) Forest nearby. But the mill has since gained a grade 2* listed status as being of historical importance.

It was a flour mill for centuries, until the early part of the last century and is now owned by Buckinghamshire County Council.

Members of Brill Society, a conservation and preservation charity, keep a weather-eye on the mill and open it for people to look inside on summer Sunday afternoons (2-5pm) for a 50p admission charge.

Jan Molyneux, Brill Society's windmill project officer, said: "In the 1970s, a steel frame was installed inside the mill to ensure it stayed up and remained in place. But this has meant the mill cannot be turned on its central post as it used to be, to catch the best winds. The sails cannot be moved either."

However, the mill is preserved on the village common that is a favourite spot for kite-flying and tobogganing down the slopes left by ancient excavations of clay for pottery making.

The first round of repairs this year followed on from the emergency closing of the mill to the public last summer.

Mrs Molyneux explained: "The county council decided the mill had to be shut for health and safety reasons. The floor was considered to be too uneven and there was a need to put in some safety handrails."

Buckinghamshire County Council came up with £20,000 to fund the work.

"Some other repairs were also done, including making the roof watertight. When the scaffolding was put up the opportunity was taken to take a close look at the whole of the structure," said Mrs Molyneux.

Conservation experts were called in and drew up a list of more work, including repairing damage caused by deathwatch beetle and other insects.

The upshot was that another £130,000 had to be spent, with money coming from grants.

Mark Bailey, natural environment team manager for Buckinghamshire County Council, said: "The mill is of national importance, both as a mill as part of the landscape and because many timbers date back to the 17th century. I think the main structure of the mill is of English oak from the Royal Forest of Bernwood."

Internal restoration was carried out sensitively to preserve the old timbers.

"Some windmills have been restored so much that they have lost their original qualities and reasons for being listed in the first place," said Mr Bailey.

At Brill mill, some of the second phase will include repair to some of the internal wooden gearings where timber has deteriorated and the decay needs to be halted.

In addition to the £130,000 spent on the second phase, the county council had budgeted for a further £50,000 to be used over the next ten years on any periodic maintenance required.