Hilsea Lines
The first means of crossing the creek was by stepping stones, followed by a single track bridge, built to allow the passage of pedestrians and horse-drawn carts to have access to Portsea Island.
[1] During the Civil War further defences were constructed by the royalists consisting of a wooden barricade mounted on the bridge backed by a small fort equipped with 4 cannon.
[2] The cannon were withdrawn on 10 August 1642 and with the barricade held by as few as eight men the parliamentarian forces were able to cross the creek two days later.
[2] The Parliamentarians then constructed their own defences of at the site of the bridge consisting of two mounds on which a total of 6 cannon were mounted.
[3] During 1756 and 1757 defensive lines were constructed on the Portsea Island side of the creek under the supervision of John Peter Desmaretz.
[6] Even before their completion the Hilsea Lines had been rendered obsolete by the 1859 Royal Commission and advances in artillery technology; as such they were the last full bastioned trace constructed in the United Kingdom.
[7] The development of rifled artillery meant that it was now possible for an enemy to occupy the high ridge of Portsdown Hill north of Portsmouth and shell the naval base from several miles away without having to attack the Hilsea Lines.
To counter the new threat a series of "Palmerston Forts" were constructed on Portsdown Hill and the Hilsea Lines were scaled back.
[13] Part of this land behind the west bastion was sold to the city of Portsmouth in 1926 which built a housing estate, a school and a recreation ground on it.
Bastion 6 is currently undergoing works to become a Nationally Recognised World War One Centre of excellence headed up by Charles J Haskell and Benjamin Edward French, a relocation from the current World War One Remembrance Centre set up at Fort Widley,[26] Portsmouth.
Bastion 5, which is owned by Portsmouth City Council, is currently in a derelict state, due to vandalism and destruction by local youths, it is listed on the Heritage At Risk Register maintained by Historic England.
Bastion 3 is used by Volunteer Groups and the Portsmouth City Council funded Hilsea Lines Ranger.
