Portsmouth Seafront and Solent Forts

The Solent Forts were built as part of the British sea defences designed to protect the port of Portsmouth against seaborne attack. Four armour-plated forts were designed by Captain E H Stewart, work on the first three beginning in 1865, overseen by Assistant Inspector General of Fortifications, Colonel W F D Jervois.

Spitbank Fort was the first to be completed thirteen years later in 1878 at a cost of £167,300. St Helen's Fort followed shortly after costing £123,311. No Man's Land Fort and Horse Sand Fort were both finished in 1880 long after the threat of a sea-based invasion from France had passed. Because both the latter forts were situated much further offshore, they were also more expensive - Horse Sand cost £424,694 and No Man's Land a further £462,500.[1]

The forts continued to be used and upgraded up until the First World War, although none of them was ever used for the purpose originally intended.