A family were left baffled after a giant hole opened up on their front lawn with rusty steps leading into the darkness.
The seven-foot deep crater appeared when shocked homeowner Emma James, 45, was mowing the lawn.
There are a few rusty steps leading down into the dark hole which currently is not big enough to squeeze down.
Mrs James, a school teaching assistant and her husband Kevin, 48, contacted the company who built the house back in 1984, but have had no luck in finding out what the hole leads to.
She said: ‘It is really odd as there are steps which lead down but we don’t know what to and there was no lid or cover on it.
‘We first thought it had a metal casing but there is concrete down there with metal steps.
‘It just seems as though it has been forgotten about but there must be a planning record somewhere to explain what it is.
‘We just want someone to come out and tell us what it is so we can sort it out. I don’t want to just leave a hole in my front lawn.’
However a spokesman for Buckinghamshire County Council has now confirmed the ‘mystery’ tunnel in fact leads to a drain covered up more than 30 years earlier.
A spokesman added: ‘Mr James confirmed to us that the opening was in the middle of his garden, nowhere near the highway, and entirely on his own private property. It appeared that it was some kind of drain that had been covered over during the development of the dwellings some 35 years before.’
The couple, who have two children, had lived in the house in Aylesbury, Buckinghamshire, for eight years with no previous problems.
But when Mrs James was mowing the lawn recently, she noticed a dip in the grass.
She said: ‘It was giving way as I was standing on it and there was clearly a little hole there so we got a shovel to move the grass roots and it just caved in.
‘It was a bit scary and we all jumped back but when we looked down we couldn’t see anything.
‘We haven’t dug anymore around it as I’m not sure if it is safe and I don’t want to make it worse.
‘I just hope that another hole doesn’t suddenly appear.
‘Someone could fall down it. Over Christmas we had the cars parked on there so they could have gone in.’
Mr James has contacted the local council and utility companies but no one is claiming responsibility for the hole.
As a safety precaution, the couple have been using cones and a piece of wood to stop people falling into it.