Officially Known as the “Brixton Storm Relief Sewer” (formerly “Effra Relief Sewer”) and constructed around 1890, it is rumored to have been built along the original course of the River Effra, the latter of which terminates into High Level Sewer No*1 at the overflow. We had previously tried to access the Brixton Relief via the Effra Main Line Sewer itself, unfortunately due to the speed and volume at its mid point, progression this way would have been suicide. As a result we went back to the drawing board and with a little research, located an access point near its outfall in Vauxhall.

The Brixton Relief is the only drain in London where there are no access passages, the ladders from above land you in the middle of the tunnel and as such were covered in all the content of the last discharge. Unable to cope with heavy flooding in the 70′s and 80′s, submerging Brixton High Street on numerous occasions, the relief was upgraded, its brick hidden behind fresh RCP, its standard manhole covers reinforced with the water tight hatches found within the tidal boundaries.

Descending into the darkness we landed in a 8ft RCP. With the tide current in and the downstream section submerged, we headed south, hoping to reach the overflow with the Effra Main Line and the High Level Sewer No*1.

Concrete is a dull construction material, it serves its purpose, no more. Its only benefit is the satisfactory grip it gives underfoot. We progressed along the uneventful tunnel for a short distance, echos reverberating back and forth between the various shape changes along the way, before reaching our target.

The tunnel opened into a chamber some 18ft tall and 20ft wide, two twin arches leading to separated overflows with the Effra Main line, the High level Sewer No*1 transported across the chamber via a raised, reinforced metal pipe. (Crude diagram below)

A slight design flaw exists with this chamber, where the Brixton relief was reinforced, the tunnels base now sits 1-2ft higher than before, as such a large volume of waste was now permanently trapped within the chamber, with nowhere to drain unless pumped. Stagnant, festering, black, nastiness. Some of the worst i had seen now sat between us and the Effra.

Thankfully i was wearing chest waders, so it wasn’t a problem. As i set off the floor sloped downwards back into the chamber, by the time i reached the High Level barrel the sludge was inches from the top. A rushing of sound and air swept under the pipe, the large 9ft brick pipe of the Effra just under this last obstacle. There was roughly a 1-2ft gap of space under the High Level pipe, just enough to squeeze through.

Under i went, and all was going well, bar the crud i was dusting with my hair. About half way through a sudden spike of cold ran down my back. Where i had bent under the pipe i had lowered my back too far, my waders now filling, and fast! By the time i reached the other side i was full, utterly soaked and my mobility down to nothing.

In truth it was mostly for nothing, the Effra Main Line was almost a meter and a half deep at this point and flowing fast, access into the tunnel too risky. Still it was interesting seeing how the original line had been messed with to incorporate Bazalgette’s interceptor.

The downstream reaches are a fairly textbook affair, although slightly more photogenic. Roughly 100m from where we first entered the tunnel bends and dives into a lower, 10ft brick pipe, flowing down past the oval to its outfall.