Description
The former ammunition magazine was built around 1938–39. The building is a single storey, rectangular-plan, reinforced concrete former ammunition store. The building comprises an inner shuttered concrete structure with a shallow pitched roof and 12 pane metal framed windows along the north and south walls. There are also buttressed outer concrete baffle walls, with earthwork banks to provide blast defence. A vehicle loading dock is located at both the east and west ends of the structure and much of the structure retains its wartime camouflage paint scheme. The magazine was built within a small area of existing woodland, which helped to camouflage the depot from the enemy.
Double steel doors and small ventilators in each gable end of the building face towards the vehicle loading docks which have concrete platforms at loading height. Between the gable ends and the loading docks are access passages through the blast wall which have metal barred gates. The building retains fixtures and fittings from its date of construction, such as lighting and electrical equipment.
The interior of the store, seen in 2015, is accessed from the doorways in each gable end. Concrete piers support the roof, and the interior is subdivided into two rows of partitioned bays for storing munitions. A number of steel doors remain in situ on the store.
In accordance with Section 1 (4A) of the Planning (Listed Buildings and Conservation Areas) (Scotland) Act 1997 the following are excluded from the listing: the two western magazines of the depot group.
Statement of Special Interest
The Former Ammunition Magazine at Northfield is a rare example of a building type which was important to both the strategic defence of the Cromarty Firth and to national defence strategy during the Second World War. It survives largely unaltered both in its exterior and interior form, and retains both its camouflage paint scheme and many interior fixtures and fittings. The building contributes to our understanding of strategic defence planning in Scotland and the United Kingdom during the Second World War.
In accordance with Section 1 (4A) of the Planning (Listed Buildings and Conservation Areas) (Scotland) Act 1997 the following are excluded from the listing: the two western magazines of the depot group.
Age and Rarity
The former armaments depot at Northfield was the central ammunition depot for the anti-aircraft (AA) batteries in the area. Of the original three magazines at the depot, all three survive, but the other two examples have been heavily altered to function as byres and storage for the farm and are not considered to be of interest in listing terms. The function of the largely unaltered magazine is still shown by a number of intact internal and external features.
Whilst there were many gun defended areas throughout Scotland during the Second World War, the concentration of batteries around the Cromarty Firth was not as extensive as those on the Clyde, the Forth and at Scapa Flow, but still involved multiple batteries. These anti-aircraft defended areas formed part of a strategic national infrastructure for defence, and would all have had munitions depots for supplying and replenishing their Heavy Anti-Aircraft and Light Anti-Aircraft batteries. For the Heavy Anti-Aircraft batteries, these came in two forms, intermediate ammunition depots, of which 9 existed in the UK, and equipment ammunition depots, of which there were 34. The depot at Ore Farm, near Lyness (LB48374) and the single magazine at Bishopbriggs are the only other known surviving examples of this type of munitions depot in Scotland.
The former armaments depot magazine at Northfield is a rare and well preserved example of its type, constructed in 1938-39. It is an example of a storage hub for ammunition to supply anti-aircraft batteries in the surrounding area, in this case the defences of Invergordon and the Cromarty Firth. It forms part of a wider group with other significant military sites associated with the First and Second World War in the area (see separate designations). The survival of the magazine at Northfield is therefore considered rare as an example of this building type.
Architectural or Historic Interest
Interior
The interior of the building is entirely designed around its function with a single large space divided into bays for ammunition storage. There is a large gap between the top of the partition walls and the building roof for ventilation purposes, to prevent the build-up of explosive gases within the building. Light comes from a combination of electric lighting, partially surviving, and a row of five 12-pane metal framed windows in both the north and south walls of the magazine. The interior appears largely unaltered since the building's construction.
Plan form
The plan form of the building follows a generally standardised design and is therefore typical for this building type. The magazine building is rectangular on plan. Inside the magazine are a total of 16 partitioned spaces, 8 along each side, for munitions storage. The concrete blast wall follows the same rough plan as the magazine itself, except at the east and west ends, where large L-shaped concrete wings extend out to form the vehicle loading bays, within each of which also contains a rectangular concrete plinth around 1m high.
Technological excellence or innovation, material or design quality
Ammunition storage buildings required very specific features to safely store the volatile explosives within. Northfield appears to generally follow the standard design for this type of depot magazine. This included extensive blast proofing in the form of reinforced concrete and earthworks, simultaneously designed to prevent any nearby blast from triggering a chain reaction within the depot and preventing any explosion within the storage building from damaging other parts of the site. The small windows and the space between the top of the partition walls and the roof allowed improved ventilation, helping to prevent the build-up of explosive gases, which stored munitions could emit over time. The loading dock facilities attached to the storage building itself helped to minimise the movement of munitions between storage and transport, helping the efficiency of the loading process and reducing the risk of an incident when moving the explosives.
The magazine at Northfield is a significant example because it retains its layout and clearly evidences its wartime function.
Setting
The building is located within a small area of woodland to the north of Invergordon. This wooded area, which predates the construction of the depot, was likely selected for the depot as the existing trees helped in camouflaging the new structures. Around the magazine are other former buildings of the depot, including the two magazines mentioned above and the former gate house, now converted to a dwelling. The site was also chosen for its proximity to Invergordon and the Cromarty Firth, as it was these strategic areas which the depot was helping to protect. The Anti-Aircraft batteries that the depot supplied would also have been positioned with this defensive need in mind.
Regional variations
There are no known regional variations which are of interest in listing terms.
The standardised form of defence infrastructure before and during the Second World War was not always followed on site, as constraints in materials and landscape sometimes required adaptation. For example, the vehicular loading bays at Northfield are at right angles to the magazine itself, which contrasts with the Ore Farm site, for example, where the loading bays are on the same line as the magazines themselves.
Close Historical Associations
The Northfield depot formed part of the nationally important defence infrastructure of the United Kingdom. Anti-Aircraft defence infrastructure in the period immediately preceding the beginning of the Second World War was built to roughly standardised forms, although with some local variation. Structures were built based on designs created in 1938 by the Directorate of Fortifications and Works of the War Office. The Invergordon area fell under the jurisdiction of 3 Anti-Aircraft Corps, headquartered in Edinburgh and one of 3 corps under Anti-Aircraft Command, with the individual corps covering the south, midland and north regions respectively. The Northfield depot therefore formed an integral part of the nationally important defence infrastructure of the United Kingdom.