Some makeshift defences protected the Tilbury-Gravesend ferry crossing of the river Thames as early as the 14th century, but it was not until the 16th century that any significant defensive structures were built there.
In 1539 Henry VIII'had 5 coastal blockhouses'built to protect the river Thames and hence the route to London. One of these blockhouses was built on the Essex bank at West Tilbury, opposite another on the Kent bank at Gravesend.
The location was strategic because the river narrows considerably at this point, which is also why the ferry crossing existed there.
During the threat of the Spanish Armada in 1588, the blockhouse at Tilbury hastily strengthened by the construction of a star-shaped line of earthworks on its landward side. This work was carried out under the supervision of the Italian engineer Frederico Genebelli.
Queen Elizabeth I positioned her army at Tilbury in readiness to repell the expected Spanish attack on London if the Armada succeeded in taking control of the channel. This position allowed the army to block the route to the capital from Essex or to cross over the river into Kent if the enemy landed there. The earthwork defences constructed at this time were not maintained and had disappeared by the mid-17th century.
Following the restoration it was decided to upgrade the fortifications at Gravesend-Tilbury. In the 1660s the Dutch-born engineer Sir Bernard de Gomme'made a number of preliminary designs for a square fort, but initially no work was carried out.
In 1670 however, new life was given to the project of building a fort at Tilbury, and de Gomme submitted a new design for a pentagonal fort with five bastions. This plan was approved by King Charles II and construction began in late September of that year.
Although this plan was to change over the 13 years it took to construct the fort, its basic form remained true to the 1670 plan. The main alteration was the omission of the water bastion, which would have been constructed out into the river, where the ground was very soft.
Although the piles were driven in, no further work was carried out on the water bastion and the idea had been scrapped altogether by 1680. Its flanks, which covered the south-west and south-east bastions, were built but there was no work projecting into the river - the old 16th century blockhouse, which was given an extra storey, formed the southern apex of the fort.
There was a flooded ditch'and a strong covered way'in front of the landward defences. At the north-west and north-east corners the covered way had a unique tenaille trace (zig-zag) form, a feature often present in de Gomme's designs. These corners of the covered way were defended by cannon.
In front of the covered way there was a second ditch. This was typical of the Dutch systems with which de Gomme was familiar and it was well suited to the flat, marshy ground of Essex.
The northern front, where the landward entrance is, was the only one to be protected by a demi-lune. The eastern and western fronts had redans'on the covered way as a substitute for a demi-lune in the ditch. To the north of the fort there was a lunette'in the outer ditch.
This lunette was designed to give additional protection to the landward entrance and it contained a small redoubt'that also served as a guardroom.
The fort's walls were intially designed as earthworks and the bastions were to have false brays'in their flanks, but in the end these false brays were omitted and the walls were revetted in brick with stone dressings (on the corners of the bastions and the cordon).
The garrison's activities were not confined to the interior of the fort - outside the Water Gate was a small guardhouse and along the riverbank either side of the blockhouse were batteries of guns that could rake ships sailing up the river. There were two entrances to the fort; the Water Gate (in the south-west curtain, adjacent to the riverbank) and the Landport Gate (in the north curtain). The Water Gate was to be the fort's main entrance, as most supplies and visitors would arrive by river.
For this reason the Water Gate was given an impressive decorative facade (see left), but the Landport Gate was relatively plain. On the inside of the fort, there were barracks for the soldiers on the west and officers' quarters on the east, with ordnance stores along the inside of the northern curtain. There was a powder magazine in the south-east bastion and a chapel next to the Water Gate. In the centre of the fort was a large open space that could be used as a parade ground.
The fort's construction was lengthy, partly due to the fact that the defences were first made as earthworks, so as to be immediately defensible, then later revetted in brick. It can be said to have been finished by 1683, but minor work continued over the following few years.
In the late 19th century Tilbury Fort was re-armed in view of developments of artillery. Newer forts had been built further downstream but Tilbury still retained some importance, along with Newtavern Fort on the opposite bank.
The eastern bastions of the fort were padded out with earth banks to protect them and gun emplacements for long-range artillery were built all along the eastern front. The batteries along the riverbank were also upgraded in this period.
Visiting Tilbury Fort
Today, Tilbury Fort is one of the best preserved bastioned fortifications in Britain. With the exception of the 19th century modifications, which included the demolition of the henrican blockhouse, the fort is in the same condition today as it was in the late 17th century.
The fort did not see action until the First World War, when its anti-aircraft guns shot down a zeppelin. A Second World War bomb destroyed the soldiers' barracks on the west of the parade ground, but other than that the interior buildings are in good condition.
The fort has undergone some restoration, including the wooden bridges with lifting sections that formed the northern entrance. This type of bridge was commonly seen in fortresses throughout Europe but those at Tilbury are among the most faithful reconstructions.
Tilbury Fort is administered by English Heritage and is open daily most of the year. Tilbury is easily accessable by rail (Tilbury Town station) or by ferry from Gravesend, Kent. The fort is a short distance from both the railway station and the ferry landing.