New discoveries through geo-referencing

Thamesmead's Tumps

I signed up to start georeferencing the RAF 1940s photographs of the Barking and Dagenham area with great glee. Comparing old and present-day maps is something I’ve always found fascinating (check out, so I jumped at the chance to be involved in this project. Delving into an area’s former life to find out what used to go on there and what traces of that activity still remain is something that captivates me. This blog post is the story of how georeferencing led me to discover a fascinating aspect of one London area’s past.

After a while of lining up street corners, crossroads and other obvious features, you would be presented with a dark photograph with virtually no recognisable landmarks on it at all – perhaps a glimpse of the riverbank and a faint railway line or trackway, long since gone, if you were lucky. But one or two of these enigmatic photographs showed some curious, obviously quite large, oval or round features in the otherwise flat grassland landscape. They had what looked like a series of moats and banks and possibly a single building in the middle.

According to the modern-day map on the left of the georeferencing screen, these were apparently somewhere in what is now Thamesmead, south of the river. But that is now a very built-up residential area with, at first glance, nothing bearing the slightest resemblance to the photographs. Not even the shoreline of the Thames is the same now. Knowing how detailed OS maps are, I thought these odd-looking features would be bound to show up on an OS map of the time, so I checked out the equivalent area on a 1940s map on But oddly that map showed nothing at all in that area other than the odd stream flowing into the Thames.

Using Google Maps satellite view, I discovered that one or two of these features still remained in amongst the streets and houses of Thamesmead and that they are now known as tumps. Curious to find out more, I googled the history of the Thamesmead area and discovered this website:

It turns out that these features were magazines, or munitions storage areas in an area that used to be part of the Royal Arsenal, known as Royal Arsenal East. They were built at around the turn of the 19th/20th century, starting in 1897, and housed munitions, propellants and explosives – hence the protective moats, banks and blast walls surrounding the storage buildings. So the fact that they were military explained why they didn’t feature on OS maps of the time.

According to the website, which also has a fascinating series of then-and-now photographs and overlays, in the 1920s the authorities began to be concerned that the 40 kilotons of munitions and explosives held in these 12 or so magazines would be enough to flatten most of the east of London and half of Kent to boot. But it wasn’t until after WWII that it was decided to close down Royal Arsenal East and distribute the munitions more safely around the country. Thus the tumps and the land of Royal Arsenal East were deserted by the early 1960s, leaving just the moats and banks in the landscape.

When Thamesmead was built, some of these magazines were retained and subsequently turned into parks and nature reserves, such as Tump 53. Others are vaguely visible in the modern-day street patterns. Luckily for us georeferencers, the Royal Arsenal History website provides plenty of highly detailed maps of the time (not the usual OS!) and equivalent modern aerial photographs with the locations of the tumps marked in, as well as then-and-now overlay map sequences. A treasure trove for old map and landscape archaeology nerds like myself. I can’t wait to find out more about another area of London!

The two images above courtesy of


Written by Kari Koonin, geo-referencing volunteer