If you walk along the riverside near Woolwich, you might spy a concrete box covered in graffiti — it’s a relic from WW2. Nicknamed pillboxes, these were part of the last line of defence for London should the UK have been invaded.
Following the fall of Dunkirk, the government decided to build a number of defensive lines across the UK in case of invasion. They were a mix of dug trenches, enhancing natural barriers such as rivers, and these concrete boxes placed often near railways (there’s one next to Putney Bridge tube station) and roads, which could be used to spy on enemy movements, and fire at them from inside.
London was ringed by three defensive lines, called unsurprisingly, Inner, Central and Outer.
Work on them didn’t get far though, as a change in tactics saw a preference towards more mobile defences, but a lot of pillboxes were still constructed, and thanks more to their formidable construction than anything else, they can still be seen.
This one next to the Thames and a riverside walkway is one of the more obvious examples to be found in London, and its placement here is in part thanks to the Woolwich Arsenal being just up the river, a key munitions factory for the war effort.
There were a number of types of design of pill boxes used around the country, and this one looks like a bit of a hybrid variant of the Essex Lozenge which were used along the sea wall. Today the concrete bunker like structure is still relatively intact – and the graffiti kids are now barred from climbing inside with two gates.
It’s taken a number of trips to get photos of the box empty, as the upper concrete lid seems to be a popular spot for sunbathers, or exercising. So it might not have serviced its original purpose, but it’s still serving a useful one today.