Calshot Castle, Hampshire, England

Calshot Castle is one of Henry VIII's device forts, built on Calshot Spit at the Solent near Fawley to guard the entrance to Southampton Water (grid reference SU488025). Also known as a Henrician Castle, Calshot was built as part of Henry's chain of coastal defences to defend England's coast from foreign invasion especially during the turbulent times after his break from the Roman Catholic Church.

It was built as a circular blockhouse with a three storey central keep in 1540 using stone from Beaulieu Abbey. The castle was subject to a number of alterations in 1584.[1] The outer walls were lowered in 1774 and the gatehouse was rebuilt in order to provide more living space. The poet Caroline Anne Bowles (1786–1854) spent childhood summers there when it was owned by a military uncle, Sir Harry Burrard.[2] The south east battery was added in 1895 but has since been demolished. The castle was in use until 1956.

It is now owned by English Heritage and visitors to the castle can park in the adjacent leisure centre car park.

Historical events involving the Castle

In late September 1651, Col. Robert Phelipps arranged passage for Charles II, then on the run after the Battle of Worcester, with a shipmaster from Southampton for transportation to France. The shipmaster was to pick up Charles at a point "between Southampton and Calshott castle," according to Phelipps's account. Unfortunately, a day or two before the appointed rendezvous, the Parliamentary forces engaged in the invasion of Jersey requistioned that very vessel. Charles and his supporters were forced to try again. Had the plan succeeded, Charles would have slipped out of England under the Castle's guns.

HISTORY OF CALSHOT CASTLE

Calshot Castle was one of the 1539 programme of 'Device' forts commissioned by Henry VIII to protect the South Coast from potential invasion from French or Spanish forces. The Solent was regarded as particularly vulnerable due to the access afford to the rich town of Southampton. William Fitzwilliam, Earl of Southampton and William Paulet, Lord St John were charged with proposing defence for the Solent region and recommended four forts; Calshot, Hurst plus East and West Cowes. Calshot itself was chosen due to the proximity of the deep water passage to the shingle spit on which the castle was to be sited. By Spring 1539 work was underway and, such were the fears of invasion, an earthwork was probably dug to provide defence whilst the stone castle was built. Completed by the end of 1540 the project was doubtless hastened by ample quantities of prepared stone quarried from the recently dissolved abbeys at Netley and Beaulieu. Built to a concentric design a circular Keep was set within a low circular curtain wall. In total it had three levels of guns; one on top of the curtain wall itself, one within the Keep and one on top of the Keep roof. On completion of Calshot the team moved onto Hurst Castle whilst further fortifications - St Andrews Castle (Hamble) and Netley Castle - were added in the Solent in 1544.

The invasion fears of Henry's reign passed unrealised but the castle remained garrisoned over the subsequent years albeit the number of serviceable weapons was allowed to reduce. Serious damage was suffered from a fire that gutted the building during the Elizabethan period but repairs were made and the castle was prepared in the 1580s to defend against potential invasion by Spain.

Calshot saw no action during the Civil War but, unlike both Netley and St Andrew's Castles, its strategic location meant it avoided slighting by Parliamentary forces. The castle remained garrisoned and continued to perform its coastal defence role throughout the eighteenth century. Upgrades were made in 1774 including lowering the curtain wall turning the gun-ports of the original structure into open topped embrasures.

Admiral Nelson's victory at the Battle of Trafalgar (1805), followed by the Duke of Wellington's later continental victory against Napoleon, reduced the threat to mainland Britain significantly. For the next 100 years the Royal Navy would rule supreme providing ultimate protection to the country. At this time the need for coastal defence diminished and Calshot became a coastguard station tasked with reducing smuggling. This duty, along with ownership of the castle, transferred to the Royal Navy in 1856.

Calshot was not upgraded as part of the major fort building associated the 1859/60 Royal Commission responding to French re-armament - those defences were built further out to block access into the Solent. However the development of the motor torpedo boat - small but fast units that could threaten devastating attacks on shipping - saw Calshot re-armed. The castle itself was too small so a separate platform was built adjacent to the Henrician fortification to house six Quick Firing guns designed to counter the threat. Searchlights were fitted in the castle to illuminate targets. A boom was also rigged across the mouth of Southampton water guarded by further defences known as dolphins - armed towers. Finally, in 1907, the roof of the Keep was modified to take another pair of Quick Firing guns.

Calshot took on a very different role in the twentieth century due to the developments in aviation. The benefits of aircraft in support of the Fleet was not lost on the Royal Navy who established a series of air-stations at coastal locations. On 29 March 1913 Royal Navy Air Station Calshot was formally formed to support sea planes. Wooden hangers were built to house upto 12 aircraft with launching rails enabling them to be moved to/from the water. Naval personnel were accommodated in local cottages or at Warsash across the water. Initially used just for experimental testing, the site took on a training role at the outbreak of World War I. By 1916 though the threat to shipping in the Channel from German U-boats was such that anti-submarine patrols were flown from the base. On 1 April 1918, with the incorporation of the Royal Navy Air Service into the Royal Air Force, Calshot was transferred to the new military arm although its role predominantly remained the same. This continued through the inter-war years but, more famously, the site also hosted the Schneider Trophy air races. These encouraged development of high speed flying and was won by Great Britain in 1931 with the Supermarine S6; an aircraft that would ultimately pave the way to the Supermarine Spitfire.

At the outbreak of World War II in 1939, the castle had been complete de-armed but a barge was moored at the site and fitted out with anti-aircraft weaponry. However as the military situation in France and the Low Countries deteriorated, resulting in the withdrawal of British forces from the continent by June 1940, the castle was fitted out with Quick Firing guns and searchlights. A supporting battery - known as the Bungalow Battery - was built on the opposite shore near Warsash in 1941 to provide additional fire-power. The two installations, along with Stone Point Battery a few miles South West of the castle, formed Calshot Fire Command. Concurrently the site also continued to function as a seaplane base – now for Short Sunderland aircraft operating in an anti-submarine capacity.

The castle was decommissioned as an airbase in the 1950s and once again became a coastguard station. But with construction of a dedicated tower for this function the old Henrician fortification became irrelevant. The castle was passed into the hands of the Ministry of Works to be preserved as a historic monument.