Eight cantilevered pillboxes at the former RAF Oakington

The structure consists of eight cantilevered pillboxes located at the former RAF Oakington, built from reinforced concrete and London Brick Company Phorpres bricks. These circular and partially subterranean pillboxes were designed to be covered with earthworks to avoid detection from both the ground and air.

Each pillbox is approximately 5.5 meters in diameter and features a disc-shaped roof made of reinforced concrete, which is supported at the center by a substantial, brick cruciform-shaped anti-ricochet wall. Surrounding the perimeter is a brick and concrete composite curtain wall that extends about 30 centimeters below the outer edge of the roof, providing an open observation and firing slit around the entire structure. The gun openings of pillboxes numbered 446 and 462 have been wholly or partially infilled with brick, and part of the curtain wall of pillbox 454 has been removed and supported with corrugated metal sheets. The entrances are traversed and stepped down into the interior.

Inside, the central anti-ricochet wall supports the roof and allows for easy access around the circumference. A 5-centimeter tubular steel rail is affixed to the inside of the curtain wall, enabling machine-gun turnbulls to slide and be locked in any position. Most of the Oakington pillboxes still retain this rail. The turnbull is still present in pillbox 445, which also features a single loop hole for a Boys anti-tank weapon aimed at the railway, along with ammunition locker recesses built into the curtain wall.

Additionally, linked to pillbox 445 is a partially below-ground, brick and concrete, detached, trenched air-raid shelter. This shelter has a concrete entrance to the north and a central concrete opening, with a trench leading into the pillbox from the south. Inside the shelter, there are two partition walls, likely intended for ablutions.