I had mapped out the route and lids from the surface, and after sitting back and navel-gazing at the information, felt certain we would get into the drainor landmark known as 'Crypt'. However, I had made several mistakes. First was to assume it was in the Frogmore Storm Relief. This was based on erroneous information found on 28dayslater forums and some computer nerd site, oddly, by Dsankt, here and Yaz’s Prourbex site (now gone) etc. However, it should be noted when written up on their excellent site, Silent uk (now gone), it is accurate. Sadly, I didn't read this before setting out. So I thought that Crypt would sit under a church in Wandsworth, there were two lids outside, so all looked good. I knew the Frogmore SR ran a few metres West from the church.

So queue a gathering of Kev and Gringz, and we tried the first lid. Down Gringz went, and reported that there was nothing we could walk or crawl in without drowning in filth. There was also a locked door, which I’d not heard of before in a drain. So Gringz came back up, and we tried the lid next to it. Kev went down and report back similar findings. Hmmm. We then went to try a succession of lids that should have opened into the Frogmore SR, but no joy. As the others were starting to despair, I said I’d check one more lid that would open into the Wimbledon Sewer. I climbed down to a short corridor that lead to another ladder that went down to an active stream in a walkable pipe. I shouted up game on, and the others came down. In the distance we could hear a rushing water noise. And headed off to find it. Me below in the main pipe of the Wimbledon sewer, standing upright a privilege denied.

Passing a side exit that I knew to be one we'd passed earlier, my map showed we were close to the end of the Wimbledon sewer. I couldn't work out what the rushing noise would be coming from, or how the Wimbledon sewer ended. The map showed it just 'ended?!' As I turned the last corner I was greeted and equally surprised by the site of the 'Crypt' junction. I was so surprised I shouted back down the Wimbledon Sewer to the others, 'This is it, Crypt!' The egg shaped pipe on the left in this pic is the end of the Wimbledon Sewer. The pipe on the right is a 2m long crossover to the other Sewer that runs in here.

With the Wimbledon Sewer behind me, this is the site I saw, Crypt. This used to go to an aqueduct, and the ends have been sealed up. The flow now goes into an interceptor at the end of the lower passage.

This used to be an aqueduct, that flowed across the Wandsworth valley. As seen in this pic below (the bowling green is still there!). However it was pulled down, and this is all that's left of it. The Frogmore Storm Relief was built to replace the aqueduct. The aqueduct used to curve around Wandsworth Stadium. The stadium was demolished in 1963, to become Southside shopping centre.

The lower middle chamber with two lower overflow weirs, dumping the two sewers either side of the camera into the interceptor below. If the sewer levels were higher, they would dump over the walls either side of the camera.

Kev gets a shot from the Wimbledon sewer side.

I sneaked in on Kev's shot on the Wimbledon side of the Crypt.

The Southern High level interceptor No.1 side of Crypt, the sealed off wall at the end where the regular flow drops into the interceptor below.

Looking upstream at the Southern High level interceptor No.1 as it comes from Putney.

Looking North and upstream, the Wimbledon sewer's smaller egg visible through the arches on the left, and the Southern High level interceptor No.1 on the right.

The first weir into the interceptor below, primarily taking the Wimbledon Sewer into its murky depths.

The second weir at the end of the passage where the sealed wall is, both sewers utilize this under normal flow. Creating the thick white U bend on the weir bridge where they both meet. You can just make out the bottom of the ladder in the side exit here, annoyingly it wasn't a lid I’d spotted before. It sits on a path between houses, and I usually spot lids from 2 wheels. Behind the camera is another side exit.

This is a plan of the chamber here, and how it originally went left to the Aqueduct. Found by Killa, from "The Engineer”, March 12 1886. No doubt a top shelf publication if this sexiness is anything to go by!

A last pic of me, and it was time to leave.

We then popped out of both side exit lids, much to the amusement of some chap thinking he'd found a quiet spot to chat on his mobile.

The below map indicates the way the Wimbledon Sewer fits into London's sewer & drain system. The Frogmore runs through the area, but has no connection with the Wimbledon sewer that we've found. To the right of this map, is the River Wandle valley, which the High Level Interceptor would have crossed. Instead it flows down to the low level. A spur from the River Wandle restarts the High Level Interceptor as it flows East.