Many thanks to Pete Hibbs ( www.pillbox.org.uk ) for bringing my attention to this WW2 artefact.
WW2 Mined Railway Bridge (Bishopstone, Seaford):
Under the bridge, on both sides of the road, there are large areas where the bricks are a different colour to their surrounding neighbours. These bricks conceal what would have been chambers within which explosives would have been placed in the event that there was an invasion. At which point the explosives would have been detonated and the bridge put out of action.
Haqre oevpx.