Built in the 1860s in response to concerns about a possible French invasion, it was the last in a series of artillery batteries that had existed on the site since the mid-16th century.

Britain's coastal defences had not been substantially upgraded since the Napoleonic Wars, but a new generation of accurate and powerful guns, mounted on fast-moving, manoeuvrable iron-clad warships, had obsoleted the existing 18th and early 19th century forts along the British coastline.

[2] The government's response to the increased threat was to appoint a Royal Commission on the Defence of the United Kingdom, which published a far-reaching report in 1860.

The Royal Commission recommended that de Gomme's red brick fortification and the two later batteries, which were incapable of withstanding modern guns, should be replaced by an armoured artillery fort on the same site.

Construction began in February 1861[5] and continued until the last of its shielding was installed in June 1872, by which time about half of the guns were already in place.

[1][4] A coastal artillery searchlight and concrete magazine were constructed to the east of the fort during the First World War, along with a machine-gun pillbox that no longer survives.

Garrison Point Fort remained in service through the Second World War and was re-armed with two twin 6-pounder Quick Firing (QF) guns to defend against fast-moving attackers such as E-boats and destroyers.

By 1944 the threat of invasion or seaborne attack had diminished to the point that the fort was reduced to care and maintenance status.

The fort was decommissioned in 1956 when the UK discontinued its coastal defence programme, and the structure was sold off to the owners of the adjacent Sheerness Docks.

[10] Garrison Point Fort is reportedly in a state of "slow decay" which has led it to be listed on the Heritage at Risk Register.