Advanced Landing Grounds (ALG’s) were small airstrips built to support D-Day. ALG’s allowed aircraft to take off and to land. They were designed for fighters such as Hurricanes and Spitfires or light bombers, such as the Mosquito, but were not large enough to support bombers such as the Lancaster or Stirling. It was originally planned to build 72 ALG’S in Southern England but some remained on the planning board. In fact only 23 were eventually built. Their potential value in supporting the D-Day landings could not be disputed but some of them were planned to be built on prime agricultural land. This led to disputes between farmers and the government. In some cases, the government had to compulsory purchase land under the Defence of the Realm Act.
The construction of those ALG’s that were built took longer than planned, primarily as the land chosen was not always the best drained. The RAF Airfield Construction Groups and Airfield Construction Groups of the Royal Engineers built them. Kent had eleven ALG’s. By any standards they were basic as it was only thought that they would be in use for a very short period of time – as proved to be the case. Other than the runway, the ALG’s had little else. Those who worked at these bases were expected to live in tents. Bomb depots were kept away from the ALG’s and were based in dense woodland. The two that served Kent were at Ham Street and Smarden.
The ALG’s were originally built with Sommerfeld runways. These were heavy steel netting held in place by metal pins that were dug deep into the ground. While they served a purpose, these runways were soon weakened by constant use. As a result they were replaced with Square Mesh Track developed by the British Reinforced Engineering Co Ltd. ALG’s used by the Americans had runways made from American Pierced Steel Plank.
ALG’s required for D-Day were finished by April 1944. The part played by aerial cover in the success of D-Day cannot be overstated as they not only ‘softened’ up enemy targets on the Normandy coast, they gave the ships carrying the troops who were to storm the beaches excellent cover against any potential attack by the Luftwaffe. Once it became apparent that D-Day was a success and that the foothold gained in Normandy was going to expand, there was no longer any use for the ALG’s in Southern England. Many were returned to those who owned the land. However, the experience gained from constructing these temporary airfields was important as dozens were built in northern France to support the Allied drive to Paris and onto the Ruhr. The problems experienced in England pre-Day were not repeated after D-Day in Northern France.
ALG’s were built in Kent at Great Chart (near Ashford), Brenzett, Edgerton near Headcorn, High Halden, Kingsnorth, Lashenden, Lydd, Newchurch, New Romney, Woodchurch, Staplehurst. AN ALG was built at Swingfield but it was not used. ALG’s were built in Sussex at Apuldram, Bognor, Chailey, Coolham, Deanland, Funtington, Selsey and Hammerwood.