Defence Structures used during the 1939 - 1945 conflict
Eastern Command Line


The four major WW11 Defence Lines

In 1940, accepting that the over-stretched defences along our coast may not be able to withstand a German landing, serious thought had to be given how to improve the situation. Throughout the country hundreds of miles of inland defence lines were initiated. They made use of the natural contours of the land such as rivers, woods, marshes etc. Where no ready barrier was evident a ditch was dug often many miles long. To be affective against tanks or armour the criteria laid down was for the ditch to be at least twenty feet wide and eleven feet deep. Fortified by infantry and artillery pillboxes, concrete anti-tank obstacles, barbed wire and gun emplacements this project was mostly completed by the autumn of 1940.

"Operation Sealion" was the codename used by the Germans for the invasion of England. When this was apparent Churchill would issue the codename "Cromwell" to all our UK forces indicating "Invasion Imminent"

The map above shows the four major defence lines in Essex.

Coastal Defence Line:- many of the areas behind the coastline were heavily fortified to prevent an invading force pushing inland. Very little remains today of these fortifications as the local councils, soon after the war were keen to clear up their holiday coastlines.

Eastern Command Line:- this defensive position originated at the mouth of the River Colne at Mersea Island, on the Essex coast,
Using the River Colne as a natural anti-tank barrier it ran north to Colchester. The capture of Colchester was unthinkable. The loss of an army barracks, communication site and a garrison town would have been a major disaster for the British.

The Command Line followed the river through the town from Rowhedge to Lexden. In the four and a half miles of its path around the town, 56 defense structures were constructed.
The line then continued its path following the river through Fordham, Ford End and onwards to Chappel.

Here it left the river and headed north following the line of the Marks Tey to Sudbury railtrack. The track alternates from deep cuttings to high embankments, between Chappel and Bures, an ideal man made obstacle.

Chappel Viaduct:-




This is where the line altered its course and here substantial defences were installed. There was a 100yd gap between the natural barrier offered by the river and the embankment to the north. This gap was heavily fortified to withstand an assault by the German army.


The armourment consisted of:-


Viaduct Fortifications

pillbox pillbox
Structure 1 - Artillery Pillbox with 6 pounder Hotchkiss Gun covering the Colchester Road.

Structure 2 -Infantry Pillbox with machine gun to fire into the road.

tank traps
Structure 3 -Each of the arches was blocked by 5ft square concrete cubes. A second row (left) was angled to provide greater protection.

Structure 4 -Three 6ft diameter cylinders filled with concrete were placed in the shallow end of the river to prevent tanks breaching the line. Presently located on the river bank.


Gun Emplacement pedestal with stainless steel pivot. Alongside the pier of the viaduct next to the pedestal (left) are the remains of two ammunition alcoves side by side.

Gun Emplacement pedestal with a (now rusty) plain steel pivot. This is unusual as most were of stainless steel.

Both positions would have benefited from the protection of the brick arches.

Structure 5-In 1942 two 29mm spigot mortars (Gun Pedestal) added beneath the arches.

By 1942, when spigot mortars were supplied to the Home Guard, the concept of “Stop-lines” had been largely discredited in favour of nodal point defence and the siting of the two spigot mortars at Chappel Viaduct probably reflects this rather than an attempt to add further to the Eastern Command Line

Structure 6 -North end of viaduct, Pillbox with anti-aircraft gun to prevent attacks from the air. No picture available.
Structure completely covered in undergrowth, located on private land.

Today, as you can see most of these defenses still survive, the three Pillboxes, the concrete cubes, the concrete cylinders together with the spigot mortar gun pedestals.

The line continued it`s path to Bures using the rail track as we said before. At Bures, the Command Line once again diverted away from the rail track back to the River Stour where it continued on towards Sudbury and finally to stopping somewhere near to Bury.

(No data available on what happened to the line at Sudbury)
Acknowledgment to supplying additional information.
Courtesy of Essex CC Heritage Site for location of structures, Oct 2003
F Nash for the SEAX records.