A "substantial sinkhole" three to four metres deep has opened up in a field - and is being given a wide berth by walkers.

The void has been spotted by those who use the route in Deal, on a piece of land which sits adjacent to Northbourne Road.

Michael Winsor spotted the missing piece of land last week and said he avoided it when walking past.

"I don’t really know why it occurred but my guess was due to recent heavy rainfall that a hollow had formed and then collapsed," he said.

"It isn’t on a public footpath but it is the edge of a field that a lot of walkers use to access the public footpaths further down.

"The hole is cone shaped, probably three to four metres deep and three metres or so in diameter at the bottom. The walls look quite smooth but maybe that is the scouring action of the water.

"At first we thought an animal had just been digging but as we got closer we could tell that it was a very large hole."

He warned others of the hole on Facebook and posted pictures of it.

His post read: "Word of warning to walkers and dog walkers who use the fields adjacent to Northbourne Road.

"There is a substantial sinkhole under a well trodden route about 150m from the road.

"The actual opening isn’t huge but it opens out beneath."

Mr Winsor added a tractor tyre is now shielding the gap: "There is a ledge all around the opening which then joins to the wall of the hole, which looked very precarious at the time so we gave it a wide berth.

"There is a large tractor tyre placed over and around the hole now which is easy to spot.

"If you venture too close you do so at your own risk, I would say."

He says the cavity looks similar to a denehole - an underground structure made up of a number of small chalk caves which can be entered by a vertical shaft.

A spokesman for the Kent underground search group reported that the feature is most likely to be a chalkwell.

"The group is regularly called out to such collapses which often occur in extreme wet weather," a spokesman said.

"Chalkwells, which are shafts for extracting chalk, can be found all over Kent and this type is likely to date from the 19th century.

"They usually consist of a short shaft opening out into a number of chambers and were dug in field boundaries, the chalk spread onto adjacent field to either break up heavy clay soil or to neutralise acidic soil."