World War II Anti-Tank Obstacles on the Foreshore

WORLD WAR II ANTI-TANK OBSTACLES ON THE FORESHORE, ISLE OF GRAIN

A line of concrete anti-tank obstacles erected circa 1940 as part of the anti-invasion defences for the Grain peninsula, Kent. The defensive line stretches approximately 570 metres along the foreshore to the north of Grain village, running north-west to south-east.

The main section consists of concrete asymmetric anti-tank pimples, also known as Dragon's Teeth, which are truncated pyramidal forms arranged in offset rows approximately 1.2 metres apart. All are fixed to a continuous reinforced concrete grid of sleepers and groins. The pimples increase in height from the seaward-facing outer examples to the inner ones, which reach approximately 1.7 metres tall. Some retain traces of red paint on their caps. Where the rows are complete, there are four pimples to each row, but because of the offset layout this creates a barrier eight deep.

At the north-west end, a double line of anti-tank concrete cubes is set at right-angles to the main line. At the south-east end, a large pile of anti-tank caltrops is positioned hard against the sea wall. These are concrete blocks with four protruding arms designed so that one arm always points upwards regardless of placement.

The condition of the line varies considerably. Two particularly well-preserved sections exist at either end: the north-western extremity extending south-east for approximately 270 metres plus the return of anti-tank cubes, and the south-eastern end extending north-west for approximately 60 metres including the caltrops. The central section has been disturbed by tidal action and coastal erosion, resulting in loss, damage and burial of some elements, making it incomplete and no longer of special interest, though retaining some value as part of the larger defensive group.

The obstacles were erected to fill a gap between the northern extent of Grain village's sea wall and the Grain and Lea marshes to the north-west. The beach at Grain was perceived as a possible attractive landing place for invasion. The line was intended to prevent enemy armoured vehicles from advancing inland, and tactically to expose the vulnerable undersides of vehicles attempting to cross the obstacles to defensive fire.