I cant really date this drain, however, it is a CSO (Combined Sewer Overflow), this is evident from the toilet tissues we came across every now and then.
The drain run downhill alongside side Stoneclough Brow and even passes under the railway viaduct.
We walked for what seemed like hours, until we ran out of steam and head height, we finally pop up out of a man hole cover for a lung of fresh air.
Tom and I walked as far as we dare before coming to a blocked section whereby waders are needed to go further.
The floor is a pain in the ass, covered with holes, as you can see the tunnel takes on many changes, turns and gradients, we did find the inlet (YET):
