THE MOST secret moated castle in England stands empty and forlorn, its future unknown and undecided after more than seven centuries of occupation. The ancestral portraits have been stripped from the walls, the books emptied in their thousands from the library shelves and elegant Georgian furniture removed by the lorryload.

Yet the castle remains as romantic as ever, perfectly reflected in the still waters of a moat which laps the walls as closely as a Venetian canal. Shirburn in Oxfordshire, at the foot of the Chiltern hills, is like Bodiam in Kent: square and symmetrical with circular towers at the corners and built when French invasion threatened in the 1370s and 1380s. Like the best medieval castles it can be entered only by means of a drawbridge.

Last month, the Earl of Macclesfield, the 9th of his line to live here, departed, evicted as a result of a court order secured by his relatives. With him has gone one of the finest private libraries in England. His ancestor, the 1st Earl, who acquired Shirburn in the early 17th century, was Lord Chancellor of England and a pallbearer at Sir Isaac Newton’s funeral. The 2nd Earl was President of the Royal Society and formed an important collection of 17th-century English mathematical manuscripts.

At Shirburn, aided by James Bradley, the future Astronomer Royal, the 2nd Earl built the best-equipped observatory in the country and made important observations of the great comet of 1743. He also took a lead in modernising the calendar, establishing January 1 rather than March 26 as the start of the new year.

Both the 1st and 2nd Earls were pupils of the mathematician William Jones, who lived in the castle as one of the family and assembled a superb scientific library which he bequeathed to Shirburn. This was added to by the 3rd Earl, who detected the horrific 1755 Lisbon earthquake in strange movements in the waters of the moat.

The cause of the melancholy break-up is the will made by the present earl’s grandfather, the 7th Earl. To avoid the death duties which would have precipitated the break-up of the 2,250-acre estate, the 7th Earl placed it in a company, dividing the shares among various members of the family. The present earl holds only a minority of shares and for 30 years he has been at odds with his uncle, his uncle’s son and latterly his brother. Meanwhile, the castle has fallen into decrepitude.

When I saw Shirburn in November the moat was all but drained and the ancient walls were shedding their protective coat of plaster, though long-overdue repairs were at last under way to stop the leaks in the roof. A still greater tragedy is that thanks to the intense privacy of successive earls, no proper photographic record of the atmospheric interiors was ever made. The castle’s history over seven centuries has only recently begun to be studied. Thirty years ago one architectural historian who crept across the park and into the garden to gain a glimpse of the hidden castle was marched off at the point of a shotgun.

A royal licence to crenellate or embattle Shirburn was granted in 1377 — seven years earlier than Bodiam. In the Civil War the castle was held for the king and besieged and shelled by parliamentary troops.

Soon after Lord Chancellor Macclesfield bought the estate in 1716 he took advice from the Surveyor-General of the King’s Works, Sir Thomas Hewett, and reconstructed the castle for what was then the large sum of £7,000. Now the 19th-century plaster has fallen away, much of the structure proves to be of pretty pink early-18th-century brick, with the arch-headed windows and thick window glazing bars typical of this date. Inside the castle are many Baroque flourishes, a grand wooden staircase with three carved balusters on each step, an imposing pillared library and veined white Baroque marble fireplaces.

George IV’s favourite architect, John Nash, remodelled the entrance hall beside the medieval gate as a Gothic-style armoury. Only the entrance tower and adjoining walls are of clearly medieval date, built of blocks of stone with arrow slits.

A series of Sotheby’s book sales are likely to raise more than £20 million for the Earl. In one cupboard was a cache of letters from Sir Isaac Newton and a collection of Newtoniana sold to Cambridge University for £6.37 million. More recently the Art Fund has led a campaign to save the Macclesfield Psalter from export to America and is just £35,000 short of the £1.7 million needed.

Yet none of this money will be spent on the castle. Today the handsome orangery stands roofless, and the dome of the elegant tempietto nearby has collapsed. As he departed, the present Lord Macclesfield said scornfully of his relatives: “They haven’t a clue what they are going to do with the place. They should sell it.” What will happen is unknown as the other side of the family maintains a staunch and discreet silence.

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