Explored with Tallginge.
I do have a bit of a fascination with London’s Storm Relief Sewers, and Serpent’s Lair was no exception.
As with most of the Storm Reliefs, they are always much filthier than you would expect given their name and presumed purpose. It therefore shouldn’t have come as much surprise that the HSR still exceeded expectations in respect of filth and nastiness.
Although we entered the system part way along its route, the report and photos are in the order of travel from east to west to best help explain things.
Earlier in the year we visited the rather impressive overflow chamber where the Counters Creek and Low Level Sewer #2 meet near Kensington Olympia. Here we carefully peered down the overflow dropshaft into the Hammersmith Storm Relief.
Ever since then, I was keen to see where the spill flows went from here and to observe the overflow from the bottom of the shaft.
The first photo shows the bottom of the shaft and the next one is the view looking back up.
Turning around 180 degrees from the first shot and the tunnel starts to take the form of a 6ft round brick pipe. This continues for some considerable distance until the pipe enlarges to a nice 8ft diameter.
Shortly after the size increase is a side passage with a drop shaft which leads up to an overflow from the Brook Green Sewer which passes above at 90 degrees to the HSR.
A short distance downstream and we came to a junction with a familiar looking 6ft brick tunnel half filled with earthy poop in which little seedlings were growing. It was the other end of the Brook Green Storm Relief that we had seen only a few days earlier. We were now below St. Paul’s Gardens.
Continuing our journey west, the tunnel takes a lovely long turn to the left followed by a relatively straight stretch and then another similar turn but this time to the right.
Not long after this, another familiar sight greeted us.
Just like the newer concrete chamber in the Brook Green SR, this chamber was very similar. However it was larger, and filled knee deep with thick festering shite which bubbled up eggy hydrogen sulphide as we trudged through it.
We had caught up again with the Duplication Branch of the HSR which joined the chamber parallel to where this photo was taken.
It continues its fetid repugnant journey downstream shown on the left hand side while the original HSR tunnel, which sits a couple of feet higher, is on the right. From here downstream the two tunnels remain relatively close to each other until they reach Hammersmith Pumping Station despite how they appear to diverge from the chamber.
Here’s a closer look at the putrid contents of the tunnel to the left. It’s perhaps not a bad thing that Smell-O-Vision failed to become a successful technology!
Turning around 180 degrees and looking back at the tunnel we have come from, you can see the Duplication branch flowing into the chamber on the left and the HSR on the right.
We carried on downstream, doing our best to avoid jets of water shooting in from a few small holes in the tunnel wall. In the distance a deep hum of about 30Hz could be heard.
After several minutes of walking we found ourselves below Hammersmith Pumping Station as expected and the source of the sound, presumably the pumps, was somewhat louder.
The steps down into the mire can be seen below on the left.
We waded into the water here in order to see into the pumping station. However the thick muddy filth got too deep for my thigh waders so I turned back here while Ginge in his chesties proceeded into the depths and up into the building above to grab some pics.
The pumping Station marks the lowest point of the HSR but interestingly the tunnel continued and took a sharp turn in a north westerly direction. We were now heading uphill again but it was barely noticeable save for the small trickle of water underfoot.
Soon we came upon a shaft with ladders leading up to a blocked off tunnel 25ft or so above us which was infested with rats.
The next section was interesting, an arched tunnel with a flat floor featuring little alcoves on each side with large cast iron panels in them. Quite what this was all about, we weren’t sure.
The tunnel then took the form of a 6ft brick pipe which went on for some distance. The silt and filth of anything up to a foot deep made progress slow and stoopy here.
Along the way, the Stamford Brook Branch of the HSR joined from a boring concrete pipe of approximate diameter 5ft.
Finally we emerged into the chamber we had been expecting to see (entering from the right), and were now quite close to Hammersmith Bridge.
About 12ft above us was a large iron flap behind which the remaining western section of the HSR ran. With no easy way into this and time running out, we focused our attention on the remaining task; one that I had not been looking forward to but needed doing.
The 4ft pipe behind the partially closed penstock leads off round a bend to join the North Western Storm Relief Sewer about 30 yards away. We squeezed under the penstock and stooped up the nasty slop filled little pipe until we emerged into the final stretch of the NWSRS, the only section we had previously left unvisited.
These final two photos are courtesy of Tallginge as I messed up the focus on my camera after stooping down that horrid little pipe and buggered up my shots.
Here is the NWSRS looking south with the other side of the 4ft pipe on the right.
A couple of minutes of walking south, yet slightly uphill, along the huge tunnel and we reached the big wall that we had been anticipating. This is the end of the NWSRS and behind the large flaps at the top of the wall is the Thames. A little dribble of water seeps in from the river and runs back into the drain.
In times of heavy rain, the Storm Relief fills right up to the top and over the wall with the back pressure pushing the flaps open and discharging into the Thames.
Once the rain stops, the remaining water in the Relief slowly drains into the HSR via the 4ft pipe we entered by.
It was now time to leave via that nasty pipe and return to street level for fresh air and liquid refreshment.
Thanks to Tallginge for the company and lighting assistance, I’ll look forward to your report on this in due course
I do have a bit of a fascination with London’s Storm Relief Sewers, and Serpent’s Lair was no exception.
As with most of the Storm Reliefs, they are always much filthier than you would expect given their name and presumed purpose. It therefore shouldn’t have come as much surprise that the HSR still exceeded expectations in respect of filth and nastiness.
Although we entered the system part way along its route, the report and photos are in the order of travel from east to west to best help explain things.
Earlier in the year we visited the rather impressive overflow chamber where the Counters Creek and Low Level Sewer #2 meet near Kensington Olympia. Here we carefully peered down the overflow dropshaft into the Hammersmith Storm Relief.
Ever since then, I was keen to see where the spill flows went from here and to observe the overflow from the bottom of the shaft.
The first photo shows the bottom of the shaft and the next one is the view looking back up.
Turning around 180 degrees from the first shot and the tunnel starts to take the form of a 6ft round brick pipe. This continues for some considerable distance until the pipe enlarges to a nice 8ft diameter.
Shortly after the size increase is a side passage with a drop shaft which leads up to an overflow from the Brook Green Sewer which passes above at 90 degrees to the HSR.
A short distance downstream and we came to a junction with a familiar looking 6ft brick tunnel half filled with earthy poop in which little seedlings were growing. It was the other end of the Brook Green Storm Relief that we had seen only a few days earlier. We were now below St. Paul’s Gardens.
Continuing our journey west, the tunnel takes a lovely long turn to the left followed by a relatively straight stretch and then another similar turn but this time to the right.
Not long after this, another familiar sight greeted us.
Just like the newer concrete chamber in the Brook Green SR, this chamber was very similar. However it was larger, and filled knee deep with thick festering shite which bubbled up eggy hydrogen sulphide as we trudged through it.
We had caught up again with the Duplication Branch of the HSR which joined the chamber parallel to where this photo was taken.
It continues its fetid repugnant journey downstream shown on the left hand side while the original HSR tunnel, which sits a couple of feet higher, is on the right. From here downstream the two tunnels remain relatively close to each other until they reach Hammersmith Pumping Station despite how they appear to diverge from the chamber.
Here’s a closer look at the putrid contents of the tunnel to the left. It’s perhaps not a bad thing that Smell-O-Vision failed to become a successful technology!
Turning around 180 degrees and looking back at the tunnel we have come from, you can see the Duplication branch flowing into the chamber on the left and the HSR on the right.
We carried on downstream, doing our best to avoid jets of water shooting in from a few small holes in the tunnel wall. In the distance a deep hum of about 30Hz could be heard.
After several minutes of walking we found ourselves below Hammersmith Pumping Station as expected and the source of the sound, presumably the pumps, was somewhat louder.
The steps down into the mire can be seen below on the left.
We waded into the water here in order to see into the pumping station. However the thick muddy filth got too deep for my thigh waders so I turned back here while Ginge in his chesties proceeded into the depths and up into the building above to grab some pics.
The pumping Station marks the lowest point of the HSR but interestingly the tunnel continued and took a sharp turn in a north westerly direction. We were now heading uphill again but it was barely noticeable save for the small trickle of water underfoot.
Soon we came upon a shaft with ladders leading up to a blocked off tunnel 25ft or so above us which was infested with rats.
The next section was interesting, an arched tunnel with a flat floor featuring little alcoves on each side with large cast iron panels in them. Quite what this was all about, we weren’t sure.
The tunnel then took the form of a 6ft brick pipe which went on for some distance. The silt and filth of anything up to a foot deep made progress slow and stoopy here.
Along the way, the Stamford Brook Branch of the HSR joined from a boring concrete pipe of approximate diameter 5ft.
Finally we emerged into the chamber we had been expecting to see (entering from the right), and were now quite close to Hammersmith Bridge.
About 12ft above us was a large iron flap behind which the remaining western section of the HSR ran. With no easy way into this and time running out, we focused our attention on the remaining task; one that I had not been looking forward to but needed doing.
The 4ft pipe behind the partially closed penstock leads off round a bend to join the North Western Storm Relief Sewer about 30 yards away. We squeezed under the penstock and stooped up the nasty slop filled little pipe until we emerged into the final stretch of the NWSRS, the only section we had previously left unvisited.
These final two photos are courtesy of Tallginge as I messed up the focus on my camera after stooping down that horrid little pipe and buggered up my shots.
Here is the NWSRS looking south with the other side of the 4ft pipe on the right.
A couple of minutes of walking south, yet slightly uphill, along the huge tunnel and we reached the big wall that we had been anticipating. This is the end of the NWSRS and behind the large flaps at the top of the wall is the Thames. A little dribble of water seeps in from the river and runs back into the drain.
In times of heavy rain, the Storm Relief fills right up to the top and over the wall with the back pressure pushing the flaps open and discharging into the Thames.
Once the rain stops, the remaining water in the Relief slowly drains into the HSR via the 4ft pipe we entered by.
It was now time to leave via that nasty pipe and return to street level for fresh air and liquid refreshment.
Thanks to Tallginge for the company and lighting assistance, I’ll look forward to your report on this in due course
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I'll have me report done soon 
