I'd been wanting to take a trip down this huge culvert (partially because of the amusing name) for some time now and the weather had been really nice recently, so it was time to give it a go.
Big Butts runs below Rochdale for just over half a kilometre and features a couple of lovely old stone bridges.
There are a few side tunnels one of which is a nice inverted brick egg leading to a stinky processor room.
Oh my god Becky!