The area around Portsmouth has long been a strategic point of defence. Portchester Castle on the northern shore of Portsmouth Harbour has played a pivotal role in defence since the Roman period, and it survives amazingly intact. In the distance from the castle you can see the white chalk outcrop of Portsdown Hill. The hill was once the site of a string of military forts built to defend invasions from the Solent. Admission is free to Fort Nelson located atop of Portsdown Hill which has been restored to represent how it would have been in the 1890s and affords magnificent views across to Portsmouth Harbour and the Meon Valley. Over 350 huge historic guns are on display here along with a museum detailing the development of artillery.
Just outside Portsmouth to the west at the northern shore of Portsmouth Harbour is Portchester Castle. It is one of the most important castles along the south coast that has played a pivotal role in defending the English coastline for hundreds of years. The Romans first built a simple fortification on the site in the third century as one of a string of castles along the south coast to ward off the increasingly rebellious Saxons. When it was abandoned by the Romans, the Saxons began adding to the site using the Roman walls as fortifications. There were further additions in the medieval period and in the eighteenth century. The Castle was in the frontline during the Hundred Years War and was the departure point for Henry V in 1415 when he travelled to Agincourt and uncovered the Southampton Plot.
It is a fantastic example of a Roman "Saxon shore" castle and it is the only Roman stronghold in northern Europe with the original walls still standing to their full height. The original Keep is also incredibly well preserved. Today it houses an exhibition on the various uses of the castle over its 1700 year history. After King Henry VII founded the Royal Dockyard at Portsmouth, the castle lost its importance and was used to house troops in the Civil War and as a goal for prisoners of war during the Dutch and Napoleonic Wars.
From all over Portsmouth and the surrounding area you can easily see the bright white chalk outline of Portsdown Hill to the north of the city. Its highest point is 390 feet and it stretches from Fareham in the west to Havant in East Hampshire. It is very much like the South Downs that cover much of East Hampshire. The hill has been a centre of occupation since prehistoric times and several Neolithic, Bronze Age, Iron Age and Saxon burial sites have been found here. The grassland that grows naturally on the chalk is species-rich with a range of flowers including hairy rock-cress, pale flax, meadow cranesbill, horseshoe vetch, bastard toadflax, early gentian, knapweed broomrape, bee orchid and fly orchid. These attract a wide range of wildlife including crickets and a huge array of butterflies including chalkhill blues, gatekeepers and marbled whites. Some of the hill is open to the public. Another interesting aspect to Portsdown Hill are the tunnels that were excavated and used during World War II. Excavation was started in 1941 and eventually included facilities such as bunks, canteen facilities, toilets and ventilation shafts.
With its high vantage point with views right across Portsmouth Harbour and the Solent Portsdown Hill's traditionally been an important defensive barrier. Because of this a string of fortifications were built due to worries that the French would invade and that Portsmouth was vulnerable. As a result of the 1859 Royal Commission's conclusions a series of forts were built along the south coast and Portsmouth Harbour was encircled by a series of forts.
Collectively these were known as the Palmerston Forts after Lord Palmerston who instigated the Royal Commission on the Defence of the UK in 1859, with a particular concentration built to protect Portsmouth's harbour and dockyard from seaward and landward attack. The forts along Portsdown Hill were Fort Wallington, Fort Nelson, Portsmouth, Fort Southwick, Fort Widley, Fort Purbrook, Crookhorn Redoubt and Farlington Redoubt. There are also a variety of pillboxes and batteries across the hills.
Fort Nelson is open to the public and has been fully restored on a nineteen acre site. It houses a collection of 350 guns and historic canons that are part of the national collection of arms and armour. Other displays within the fort cover a variety of military stories and include Saddam Hussein's infamous "Supergun" and the trebuchet from the movie "Gladiator". Galleries in the fort trace military history and the development of artillery through thousands of years. There is a gift shop on site where you can buy toys and gifts and military related books and souvenir guides.