Group of seven World War II fighter pens at the former airfield of RAF Kenley


Heritage Category: Scheduled Monument

List Entry Number: 1021243

Date first listed: 06-Sep-2004


Ordnance survey map of Group of seven World War II fighter pens at the former airfield of RAF Kenley
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This copy shows the entry on 19-Jan-2019 at 23:06:52.


The building or site itself may lie within the boundary of more than one authority.

County: Greater London Authority

District: Croydon (London Borough)

National Grid Reference: TQ 32527 57681, TQ 32680 57608, TQ 32918 58429, TQ 33067 58470, TQ 33207 58020, TQ 33228 58171, TQ 33287 58274


Legacy Record - This information may be included in the List Entry Details.

Reasons for Designation

The importance of defending airfields against attack was realised before the outbreak of World War II and a strategy evolved as the war went on. Initially based on the principle of defence against air attack, anti-aircraft guns, air raid shelters and dispersed layouts, with fighter or `blast' pens to protect dispersed aircraft, are characteristics of this early phase. With time, however, the capture of the airfield became a more significant threat, and it was in this phase that the majority of surviving defence structures were constructed, mostly in the form of pillboxes and other types of machine gun post. The scale of airfield defence depended on the likelihood of attack, with those airfields in south or east England, and those close to navigable rivers, ports and dockyards being more heavily defended. But the types of structure used were fairly standard. For defence against air attack there were anti-aircraft gun positions, either small machine gun posts or more substantial towers for Bofors guns; air raid shelters were common, with many examples on each airfield; and for aircraft, widely dispersed to reduce the potential effects of attack, fighter pens were provided. These were groups together, usually in threes, and took the form of `E' shaped earthworks with shelter for ground crew. Night fighter stations also had sleep shelters where the crew could rest. For defence against capture, pillboxes were provided. These fortified gun positions took many forms, from standard ministry designs used throughout Britain and in all contexts, to designs specifically for airfield defence. Three Pickett-Hamilton forts were issued to many airfields and located on the flying field itself. Normally level with the ground, these forts were occupied by two persons who entered through the roof before raising the structure by a pneumatic mechanism to bring fire on the invading force. Other types of gun position include the Seagull trench, a complex linear defensive position, and rounded `Mushroom' pillboxes, while fighter pens were often protected by defended walls. Finally, airfield defence was co-ordinated from a Battle Headquarters, a heavily built structure of which under and above ground examples are known. Defences survive on a number of airfields, though few in anything like the original form or configuration, or with their Battle Headquarters. Examples are considered to be of particular importance where the defence provision is near complete, or where a portion of the airfield represents the nature of airfield defence that existed more widely across the site. Surviving structures will often be given coherence and context by surviving lengths of perimeter track and the concrete dispersal pads. In addition, some types of defence structure are rare survivals nationally, and all examples of Pickett- Hamilton forts, fighter pens and their associated sleep shelters, gun positions and Battle Headquarters closely associated with defence structures, are of national importance.

Although Kenley no longer has the pillboxes and other elements of an airfield defence surviving, it is the only example identified through a national survey to retain nearly all of its dispersed fighter pens. As such, and in association with its historical significance, it is a nationally important monument which demonstrates both planned defence of aircraft from attack while on the ground and the success of this policy, as so few aircraft were lost on the ground despite repeated and heavy aerial attack.


Legacy Record - This information may be included in the List Entry Details.


The monument, which falls into seven separate areas of protection, includes part of the former World War II fighter station known as RAF Kenley. These seven fighter pens are part of a group, originally numbering twelve, dispersed around the runway perimeter track of the airfield. Seven survive within the monument and a further four pens are the subject of a separate scheduling. During World War II fighter aircraft were considered to be very vulnerable when on the ground either from air attack, or, during the early years of the War, from possible ground attack, and elaborate precautions were taken to prevent any loss of aircraft when not in action. As a result, fighter aircraft were often held in dispersed pens located around the perimeter of the airfields but with easy access to the main runways. These pens were often constructed in an E-shape with two bays, one for each aircraft. At Kenley all but one of the original 12 pens survive, providing protection for up to 24 aircraft at a time. Kenley was first used as a Royal Flying Corps aerodrome in 1917 although the buildings associated with the grass flying field have all now gone. An Act of Parliament in 1939 following agreement to provide all-weather runways and perimeter tracks for critical fighter stations led to the expansion and rebuilding of RAF Kenley to provide two 800 yard (732m) runways which were completed in December 1939. By April 1940 all 12 fighter pens had also been completed and the Station was fully operational. The aircraft based at Kenley formed part of 11 Group and it was able to house two squadrons of twelve aircraft each in the fighter pens and a further squadron dispersed on open hard standings. Kenley was subjected to some of the most sustained attacks on fighter stations by the Luftwaffe in 1940. On 18th August one raid led to the loss of three personnel, three hangers and two aircraft ; photographs of an attack on a fighter pen appeared in the German Der Adler magazine. On 30th August 39 personnel were killed and 26 wounded and on the following day the operations block was damaged. Despite these sustained raids Kenley continued to launch fighter aircraft and played a vital role throughout the Battle of Britain and the later Blitz of London. The eight standard Fighter Command Works aircraft fighter pens within this scheduling were built in three groups. Two lie to the north, immediately west of the end of the main runway. A further four lay east of the perimeter track on the east side of the airfield with the site of the former battle headquarters to their south and the final two lie on the south west side of the airfield, close to the southern end of the main runway on the western side of the perimeter track. Together with four further pens on the north side they provided a 360 degree dispersal of aircraft and allowed at least some operational capability even if one of the runways or the perimeter track were damaged or fell to enemy ground assault. The layout of a twin fighter pen consists of an E-shaped set of stone and brick dwarf retaining walls and earthwork traverses which protected three sides of, and separated, two bays, each for one aircraft. These measured about 50m along the rear axis and 22.5m along the side with the banks measuring 6.5m wide. The two bays each measured approximately 16.5m and provided ample room for one Spitfire or Hurricane aircraft in each. At the rear of each pen is a precast concrete Stanton type air-raid shelter for up to 25 men with access from either bay. All modern fences, gates and all post-August 1946 ground surfaces are excluded from the scheduling, although the ground beneath all of these features is included.

MAP EXTRACT The site of the monument is shown on the attached map extract. It includes a 2 metre boundary around the archaeological features, considered to be essential for the monument's support and preservation.


The contents of this record have been generated from a legacy data system.

Legacy System number: 30904

Legacy System: RSM


PRO station record book, AIR 28/419, Operations Record Book, (1939)
See 146460, (1939)

End of official listing