Netley Castle

Until the last years of Henry VIII the Crown had largely left coastal defence to local lords and communities, and English fortifications were limited in scale: simple blockhouses and towers in the south-west and along the Sussex coast, with a few more substantial works in the north. Maritime raids were common while France and the Holy Roman Empire were at war with one another, but an actual invasion of England seemed unlikely. Henry's break with Pope Paul III in 1533, made in order to annul his marriage to Catherine of Aragon, changed that calculation. Catherine was the aunt of the Emperor Charles V, who took the annulment as a personal insult; France and the Empire declared an alliance against Henry in 1538 and the Pope urged them to attack. In 1539 Henry issued the order known as a "device", giving instructions for the "defence of the realm in time of invasion" and for the building of forts along the coast.

Netley Castle was one of them, raised on Southampton Water between the mouths of the Hamble and the Itchen, 250 metres south-west of Netley Abbey. The abbey had been dissolved shortly before, and material from the site was reused in the fort. William Paulet, later Marquess of Winchester, oversaw the work, which took place in either 1542 or 1544, and Henry granted him estates to pay for the fort and its garrison. The castle took the form of a central keep 19.5 by 14 metres across, with deep embrasures along the battlements and a gun platform to either side, on a design resembling that at nearby Southsea. Its first garrison was two soldiers, six gunners and a porter under a captain.

Netley was still garrisoned in the mid-1620s and was probably in active service when war broke out between Charles I and Parliament in 1642. At the end of that year Captain Swaley, a Parliamentary naval commander, seized the castle and decommissioned it as a fortification. It was brought back into use during the Interregnum out of concern that the Royalists might invade, then abandoned as obsolete after the restoration of Charles II. By the time Alexander Pope visited in 1734 the fort was overgrown and in ruins.

William Chamberlayne inherited the castle in 1826 and the following year built a crenellated tower at its south-east end, taking up a proposal by the antiquarian Horace Walpole that the ruin be made habitable. A description from about this time placed it "in the midst of a thicket of trees, on a little hill close to the beach", forming "a striking object seen from the water". Artists took to it: J. M. W. Turner sketched the castle and its new tower, probably in 1832.

George Hunt leased Netley in 1841 and turned it into a private house under the architect George Guillame. By the time Hunt left in 1857 the building had an oriel window overlooking the sea, and the battlements had been blocked in to carry a second storey. George Sherriff held the lease from 1868 to 1873 and walled the front of the property in stone. Sir Henry Crichton bought the castle in 1881 together with its gardens, orchards, pond and boat house, and the architect John Sedding remodelled it between roughly 1885 and 1890 into a Gothic house with a further storey and a new wing.

Crichton died in 1922 and his widow remained in the house until her death in 1936, when the property and its grounds were sold at auction. Middlesex County Council bought the castle in 1939 and converted it into a nursing home for elderly men; it passed to the National Health Service in 1948 and continued in that use. The building proved expensive to maintain, the surrounding land was sold off piece by piece, and the Southampton University Hospital NHS Trust closed it in 1998.

The property developers Fairmist Limited bought Netley in 2000 and converted it into nine private residential flats at a cost of £1.7 million, an archaeological survey of the site being made in the course of the work. The Tudor fort survives within the centre of the three-winged house, which was listed at Grade II* in 1974 and is also protected as a scheduled monument.