Groundwork & Foundations

Who to contact after finding tunnel in garden

Anonymous user 23/02/2024 - 3.23 PM

I wanted to dig some holes for planting in the garden (apx 20-50cm deep). I tried to proceed carefully and checked the house plans, made sure it wasn't near an inspection hatch and also submitted a 'line search' to check for utilities before digging, but have unearthed a tunnel in the garden. About 5cm below the surface, I found two old bricks with loose cement - thought it was just builders rubble, so gave it a wiggle and pulled these out by hand, but it collapsed inwards and turned out to be the top of an archway. It looks to be a brick tunnel apx 1m across. There wasn't anything in the tunnel like water/sewage/other pipes (and we're on the mains, so wasn't expecting a septic tank or similar) so I'm not sure what it might be or who best first point of contact would be. Any suggestions on first point of contact to investigate what this might be, please? --Updated Many thanks for the suggestions! We got a camera down there and I can see the walls slope downwards in 3 directions (can't see the 4th), making a dome shape. So I'm thinking possibly an old sess-pit. Doesn't appear to be a current drainage/water supply asset, but going to reach out to Thames Water just in case, then probably get it filled.