As I know how much everyone loves these debates, here's a scenario:
My Grandad used to live in Cornwall, and owned a house in the sticks, with garden, and another bit of land directly opposite.
About 15 years ago he moved back to Hampshire and sold the house, but kept the bit of land opposite.
About 3 years ago he was contacted by the person who owns the house next door (who I don't think has a garden), who asked if his children could play in his field. Grandad said of course that is fine.
Recently however Grandad was informed by a relative who still lives down there (Grandad is in his 80's and so is unable to travel to Cornwall very often) that this man has laid down some hardstanding in the field, erected a five bar gate, and is using the land to park vehicles. He had also set up some fencing where he was apparently planning to keep chickens, although has now taken it down.
We are worried that the neighbour may be planning to claim some form of squatters rights over the land, and take ownership of it himself. Is there any risk of this? What do people suggest we do?