Looking for further information on the Northern Lines? Try Crownhill Fort or Western Flank defences.

The Northern Lines were constructed in the 1860s to provide landward defence for Devonport Naval Base. The eastern flank consisted of six installations – Bowden Fort, Eggbuckland Keep, Forder Battery, Austin Fort, Efford Fort and Laira Battery. These collectively dominated the high ground between Crownhill and the River Plym.





In 1858 France launched the world's first seagoing Ironclad warship ('La Gloire'; the Glory) instantly rendering the wooden sailing ships of the Royal Navy obsolete. The British, whose prosperity depended upon the navy’s ability to protect both the homeland and the increasing number of colonies overseas, panicked. In 1859 a Royal Commission was established to review coastal defence arrangements and their final report, published in February 1860, concluded that Britain was vulnerable. To mitigate, they proposed that vital facilities across the coastal regions, including the Royal Navy dockyard at Devonport, should be protected by a series of new forts. The recommendations were accepted by the Government of Lord Palmerston and represented the biggest peacetime military infrastructure project in British history.


The Northern Lines


In order to protect Devonport naval base, any enemy force needed to be kept out of artillery range of the dockyard. Accordingly, fortifications were not only built to protect the sea entrance into Plymouth Sound, but were also constructed on the high ground surrounding the area. These land forts were divided into three distinct schemes consisting of the Northern Lines, the Western Lines and the Staddon Lines. The largest of these was the Northern Lines which were required to occupy an expanse of high ground to the north of Plymouth stretching from the River Plym in the east to the River Tamar in the west. The primary fortification in this defensive line was Crownhill Fort but it was flanked by a series of secondary forts, batteries and earthworks that acted as a single unified scheme.


The Eastern Flank


Extending south-east from Crownhill Fort were a series of installations and earthworks constructed along the high ground and intended to provide unbroken coverage of the landward approaches to the River Plym. The fortifications consisted of Bowden Fort, Forder Battery, Austin Fort, Efford Fort and Laira Battery. Eggbuckland Keep was also built to sustain the garrison and provide a redoubt. Work started on all six structures in 1863 initially under a private contractor but, when the scale of the building project overwhelmed the company, they were finished by the Royal Engineers. In addition to the forts and batteries, a military road linked all the sites of the Northern Lines. Where necessary, an earth bank was built to the immediate north of the road to prevent its traffic being visible or vulnerable to enemy fire.


Bowden Fort

Bowden Fort occupied a salient point overlooking the lower ground to the immediate east of Crownhill Fort and providing essential defence for that facility. It was configured in a polygonal arrangement and was intended to be fitted with twelve guns, mounted on open batteries, plus three mortars. Defensive arrangements included a ditch that ran to the west and north of the site and was protected by a caponier and counterscarp gallery. Casemated accommodation was provided for sixteen men, the small number being due to the presence of the main barracks at nearby Eggbuckland Keep. The fort was never fully armed and in 1885 it was fitted with just seven 7-inch Rifled Breach Loading guns. By 1893 four of these had been replaced by 64-pounder Rifled Muzzle Loading guns. The fort was disarmed before 1900 but continued in military ownership until 1963. It has now been modified to serve as a garden centre.


Eggbuckland Keep

Eggbuckland Keep was originally intended to be one of four such structures forming part of the Northern Lines to provide accommodation facilities for the garrison. However, in the end only Eggbuckland was built to serve the neighbouring Bowden Fort, Austin Fort and Forder Battery. The five sided, two storey structure was constructed between 1863 and 1871. Casemated barracks were provided for 230 personnel and a tunnel connected the site to Forder Battery enabling personnel to quickly man the guns if required. The barracks were originally intended to be equipped with five 7-inch Rifled Breach Loading guns, located in the caponiers, but it never received any of its original weapons outfit. However, by 1893 three 0.45mm Machine Guns had been installed. The site was disposed of by the military after World War II and the site now serves as a DIY store.


Forder Battery

Forder Battery occupied a forward position between Bowden and Austin Forts. Like those installations, it looked out over the steeply sided Forder Valley. It was configured in a polygonal layout and was intended to be fitted with eighteen guns including twelve 7-inch Rifled Breach Loading guns. Defensive arrangements included a dry ditch that ran in front the site between Bowden and Austin Forts - both of which could fire along its length. No accommodation was provided due to the presence of Eggbuckland Keep which was connected to Forder by a tunnel. The battery was decommissioned by the military in 1900 and is now in use by British Telecom.


Austin Fort

Austin Fort was aligned facing north-east overlooking the Forder Valley with commanding views of the surrounding area. It was configured in a polygonal arrangement with its original weapon fit planned to include fifteen guns in open enclosures and five mortars in dedicated pits. However, it was never fully armed and by 1885 only five 7-inch Rifled Breach Loading guns and three 8-inch Howitzers had been installed. By 1893 this had been reduced to four 64-pounder Rifled Muzzle Loading guns. The site was completely surrounded by a dry ditch and this connected to an extension which led north-west running in front of both Forder Battery and Bowden Fort. The ditch was overlooked by a two storey guardhouse with a line of fire along the extended trench. Despite the proximity of nearby Eggbuckland Keep, the fort was equipped with casemated accommodation for 60 troops. The site was used by the Devon and Cornwall Auxiliary Unit during World War II. The military disposed of the fort in 1958 and it is now used by the City Council.


Fort Efford

Fort Efford was built upon a hill overlooking a bend in the River Plym and with a clear line of fire to the north-east and east. Like the other forts of the northern lines, it was configured in a polygonal arrangement and was originally intended to mount eighteen guns in open enclosures and a further three in haxo casemates. However, by 1885 only eleven 7-inch guns had been installed although a further five guns were added by 1893. The steep natural scarping of the site meant no ditch was required. The site included accommodation for 113 troops. The military disposed of the site in 1961 and it was purchased by Plymouth City Council who let it out to the Showman's Guild.


Laira Battery

Laira Battery was built on a foothill to the south of the Fort Efford and operated in direct support of that facility. It was aligned on a south-west axis with clear arcs of fire across an extended stretch of the River Plym and the associated valley. The main armament was intended to consist of ten guns in open emplacements and a further three in haxo casemates. However, only eight 7-inch Rifled Breach Loading guns had been installed by 1885 and in the subsequent few years five of these were removed and replaced with just two 64-pounder Rifled Muzzle Loading guns. Like Fort Efford, the strong natural position of the battery meant no defensive ditch was required. Accommodation was provided for 32 personnel. The military disposed of the battery in 1961 and it now serves as a machine plant hire depot.





Dyer, N (2014). British Fortification in the late 19th and early 20th centuries. Inky Little Fingers Ltd.

Historic England (2016). Efford Fort and Emplacement, List entry 1021135. Historic England, London.

Historic England (2008). Austin Fort and section of military road, List entry 1021380. Historic England, London.

Historic England (2005). Eggbuckland Keep, List entry 1020543. Historic England, London.

Historic England (2004). Bowden Battery, List entry 1021365. Historic England, London.

Historic England (2003). Laira Battery, List entry 1021134. Historic England, London.

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Kinross, J (1999). The Palmerston Forts of the South West: Why were they built? BBNO Battery Books.

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Marriott, L (2015). West Country Forts and Castles. Air Sea Media.

Moore, D (2011). Arming the Forts. Speedyprint, Gosport.

Moore, D (2010). Austin Fort.

Moore, D (2010). Bowden Fort.

Moore, D (2010). Egg Buckland.

Moore, D (2010). Forder Battery.

Moore, D (2010). Fort Efford.

Moore, D (2010). Laira Battery.

Pye, A (1996). The Historic Defences of Plymouth. Cornwall County Council.

Wass, S (2010). The Fortifications of Plymouth. Polyobion.

Woodward, F.W (1997). Forts or Follies? Palmerston Forts. Halsgrove.

What's There?

None of the forts or batteries of the eastern flank are open to the public but the exterior of all can be viewed from roads or rights of way.

The Northern Lines and the Victorian Defences of Plymouth Sound. The Victorian defences were intended to ensure any enemy force was unable to close within artillery range of the important Royal Navy dockyard in Devonport. Crownhill was the lynch-pin of the Northern Lines and further fortifications extended either side with those to the east covering the Forder and Plym valleys. The forts were linked by a military road which, where necessary, was camouflaged by an earth rampart intended to conceal movement along its length. In the wider area there were two other landward defensive schemes - the Staddon Lines (centred on Fort Staddon) and the Western Lines (centred on Tregantle Fort). A significant number of forts also protected the sea approaches. Details of all the forts of Plymouth Sound can be found here.

Bowden Fort. This fort covered the ground to the immediate east of Crownhill fort. It is now a garden centre. The fort's impressive vantage point over the Forder valley can be clearly appreciated.

Eggbuckland Keep. The last Keep to be built in England, this facility was intended to provide accommodation for troops manning Forder Battery and Bowden Fort. The site is now in use as a DIY store.

Forder Battery. This battery projected forward of the adjacent two forts with clear arcs of fire over Forder Valley. The site is now in use by British Telecom.

Austin Fort. The fort extended the coverage across the Forder Valley. The site is derelict with no public access.

Military Road. The military road survives near Austin Fort. Note the earth bank designed to conceal movement along the road.

Fort Efford. Many people pass this fort without even realising it is there. Towering over the distinctive Sainsbury’s supermarket, the site occupies the tree covered hill just beyond. The fort was built to prevent an enemy force advancing along the Plym valley. The site is currently occupied by members of the Showman's Guild. Based on our experience, visitors interested in the fort are not made very welcome.

Laira Battery. This battery was built to augment the fire-power of Fort Efford. It had a clear field of fire across a significant stretch of the River Plym. It is currently in use as a plant hire depot but directly abuts a public road.

Getting There

The six installations are spaced over a three mile stretch. Visitors can either park at Crownhill Fort and walk between the sites (noting there are some busy roads) or drive to each site individually.


Crownhill Fort. This fort is well sign-posted from the A38. When open to the public (normally one day per month, Summer only) there is dedicated car park within the fort. Otherwise on-road parking is possible.


Bowden Fort. The fort is found on Fort Austin Avenue near the T-junction with Church Hill Road. There is a large car park for customers of the garden centre.


Eggbuckland Keep. This site is accessed from Shirburn Road. On-road car parking is possible.


Forder Battery. The battery is found on Fort Austin Avenue at the point near the T-junction with Cardigan Road. The site is occupied by a large radio mast making it easy to find. On-road car parking is possible.


Austin Fort. This fort is found off Fort Austin Avenue at the point where it connects with the Military Road. On-road parking is possible.


Fort Efford. This site is accessed from the Military Road which is accessed from A374. The turn off to the fort is marked 'Private'. On-road parking (on the Military Road) is possible.


Laira Battery. This site is found on the Military Road just of the A374. On-road parking is possible.

Crownhill Fort


50.412483N 4.13026W

Bowden Fort

Fort Austin Avenue, PL6 5NU

50.405307N 4.117588W

Eggbuckland Keep


50.403622N 4.112128W

Forder Battery

Fort Austin Avenue, PL6 5NY

50.404349N 4.110517W

Austin Fort

Fort Austin Avenue, PL6 5TQ

50.399633N 4.103943W

Fort Efford


50.390333N 4.092767W

Laira Battery

Military Road,  PL3 6EL

50.387620N 4.091041W