I came across this quaint little tunnel whilst scouring the banks of the Irwell. It looks to have been blasted into the local sandstone and finished in pick. It's straight and the height varies from around 4ft, with some parts more stoopy.
The water has cut into the stone at points to produce a crack which gives a little more room to stand. A brick shaft at the tunnel's far end extends up into daylight and houses a small pipe which is the source of the water.