Thursday, 15 October 2026

The Flight of GX 10135 - Down the A303 on an August day, 1940

On 18 August 1940 a German reconnaissance aircraft crossed south Wiltshire with three cameras running. From near Mere it followed the line of the A303 east past Chicklade, Wylye and Yarnbury Castle to Winterbourne Stoke, passed Stonehenge, turned south over the Avon and ran down past Old Sarum to Salisbury. Its prints are in the US National Archives. Joined in order, they make a strip some 45 km long, and the films below fly it again. A companion to The Luftwaffe's Wiltshire and to the film of sortie GX 10484, flown three months later.

Sortie GB 956

NARA files the prints as box GX 10135. The titling strip on each reads GB 956 with the camera letter and the date, and each clock dial is pencilled "18.8." with the camera letter. The day is the one later called the Hardest Day of the Battle of Britain: the Luftwaffe made heavy raids on Kenley, Biggin Hill, West Malling, Hornchurch, North Weald, Ford, Gosport, Thorney Island and the Poling radar station. No record found links this sortie to those raids, and none records reconnaissance over Wiltshire that day.

Three cameras

Three cameras ran together, and all three survive for this stretch:

  • L, a long lens of 502.48 mm: 17 frames, exposures 27–43, each about 5 km across on the ground.
  • R, a second long lens of 505.13 mm aimed off to one side: 12 frames, exposures 19–30. Its frames overlap the L frames by only 5–25%, and they are not used in the films.
  • S, a wide-angle camera: 9 frames, exposures 16–24, each about 13–15 km across. Each S frame contains three to five whole L frames, at roughly 2½ times less detail.

The L run has a gap. Over the Plain the aircraft turned through about 110°, and L 36 and L 37 do not overlap their neighbours. The S frames do: the nine of them join without a break from Mere to Downton, across the turn. So the films fly over the S strip and use the L frames for the close views, at Yarnbury Castle, Stonehenge and Salisbury Cathedral.


The nine wide-angle frames joined, north up. Places marked at their Ordnance Survey positions. Luftwaffe, 18 August 1940, NARA RG 373, GX 10135.

The camera clocks

On the L and R prints the dark mark near twelve is the hour hand; the minute hand is hidden under the pencilled date. The S clocks show both. Their minute hand moves from about 37½ on S 16 to about 44½ on S 24: roughly a minute between wide frames, and seven to nine minutes for the whole run. The hour hand stands just short of twelve. Neither the time zone nor whether the clocks were set together is stated on the prints.



The S-camera clock on the first and last frames, S 16 and S 24. NARA RG 373, GX 10135.

The centres of the S frames are 4.9–7.1 km apart, 45 km in all. Over seven to nine minutes that is a ground speed of roughly 300–390 km/h. If the film is 30 × 30 cm, as on GX 10484, the 5 km cover of the 502 mm lens puts the aircraft about 8 km above the ground. Both figures are estimates; no record names the aircraft or its unit.

Along the A303

The road was numbered the A303 on 1 April 1933, so it carried that number on the day of the flight. In 1940 it still ran through Wylye, bypassed in 1975, and through Amesbury, bypassed in 1969. For the first half of the run the aircraft follows it closely, which is why the films use it to keep the viewer oriented.

Yarnbury Castle

Yarnbury Castle, north up, from L 34. The A303 passes the southern edge of the hillfort. Luftwaffe, 18 August 1940, NARA RG 373, GX 10135.

The Iron Age hillfort lies beside the A303 west of Winterbourne Stoke. Next to it, white lines of freshly dug chalk mark army training trenches. The ground was commandeered by the Army in 1916, and on these prints the trenches are still bright, so the digging was recent.

Stonehenge, August 1940

Stonehenge, north up, from L 37. Luftwaffe, 18 August 1940, NARA RG 373, GX 10135.

Stonehenge falls on L 37, the frame at the turn. Beside the stones run the A344 and the old crossroads with the byway that was moved west in 1967. The 1917 aerodrome to the west closed in 1921; its buildings were demolished from 1927 and cleared by the early 1930s, and the Stonehenge Café and the custodians' cottages went in 1938. By August 1940 only the marks of these buildings remained. In high summer the grassland around the stones is pale and the tracks across it stand out, against the dull ground of the November photographs of GX 10484.

Old Sarum and Salisbury

After the turn the aircraft ran south down the Avon. Old Sarum, the Iron Age hillfort and site of the first Salisbury, passes on the way; beside it lay RAF Old Sarum, where No. 225 Squadron had been based since June 1940. The run ends over Salisbury, the cathedral and its Close in the middle of the frame, and continues south towards Downton.

Salisbury Cathedral and the Close, north up, from L 40. Luftwaffe, 18 August 1940, NARA RG 373, GX 10135.

Joining the frames

The nine S frames were matched on their common ground and fitted together in one adjustment; neighbouring frames agree to 2–4 scanned pixels for most pairs, 5–9 near Mere. Each L frame was then placed on the S strip, to within about a pixel of the S scan, so the close views drop into the wide flight in the right place. To label the films and set the north arrow, the strip was matched to modern imagery on some 750 field edges and hedgerows, to within about 70 m over most of it and 200 m at worst. Each part of the strip comes from one photograph only, so nothing is doubled at the seams.

Notes on the films

Three versions. The captioned film (3:05) names places as they pass and has short notes on the cameras, the road, Yarnbury, Stonehenge, Old Sarum and the cathedral. The director's cut (2:41) is the photographs alone, with a north arrow. The short (0:40) opens on Stonehenge, flies the A303 to Yarnbury and ends over Salisbury. All three run at four to five times real speed. The backs of the GX 10135 prints have not been scanned, so there are no interpreters' notes to quote. The music is original.



Sources

All photographs: Luftwaffe, 18 August 1940; US National Archives, RG 373, GX 10135, listed as Use: Unrestricted. Modern imagery (Esri) was used for matching only and is not reproduced. Frame matching, measurements and films: T. Daw. Methods and scripts: github.com/TimDaw37/wessex-films.

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