`Hands off that fence or you'll be hearing from my solicitor'

Quarrelling over the garden fence is something that sensible neighbours should avoid at all costs. Take the chap who recently took a chain-saw to a 6ft boundary fence he claimed his neighbour had erected on his land. That moment of rampant Nimbyism may have to be settled by the County Court, leaving both parties with massive legal bills.

"Disputes like this can get very petty and confrontational, and they can be difficult to resolve," says John Crossley, of Black Horse Agencies. "They are more often about 6in of land than 6ft. It is best to avoid disputes unless the land has material value. But people get very emotional about it."

Neighbours most likely to involve themselves in a boundary dispute are those who live alone, says David Powell, chairman of the Royal Institution of Chartered Surveyors Boundary Practice Panel. "You may have a very neat, fastidious pensioner living next to a hard-working young couple. They come home, see the fence has blown down and put it up again. The chap next door will spend the rest of his life trying to prove they have moved it 8mm."

Powell's preferred client is the one who believes a boundary has been moved and simply wants him to say whether he is right or wrong, and, if he is right, whether it is really worth bothering about. "But if I go in and see they have covered the floor with the Reader's Digest Guide to the Law, videos and aerial photographs, I know there will be trouble."

Knowing exactly where to draw the boundary line is not as easy as most warring neighbours believe. The Land Registry entry will be helpful only over larger pieces of land. "A line drawn on the Ordnance Survey map is accurate only to within half a metre," says Powell. "And the Ordnance Survey doesn't show boundaries; it shows things. They will map a hedge, but that may be 4ft inside the boundary. The deeds should give you the extent of your property."

Yet even these may not be conclusive. "Some will give exact acreage, or give a measurement of 245ft 5.5ins. In other cases the plan may say the frontage is 50ft, but the text may say `50ft or thereabouts'." The deeds may resolve a dispute over who owns a boundary, if not its exact position. "The plans may show a boundary line with T-marks. These point into the garden of whoever is responsible for the fence or wall." If all else fails, Mr Powell may resort to old photographs for clues, or get down on his hands and knees and dig for ancient fence posts.

But prevention is better than cure. Before buying a property, find out who is responsible for trimming the hedge or resurfacing a shared drive. When you move in, photograph the boundaries from an upstairs window, and repeat this once a year when the trees are bare so that you have an unobstructed view.

It is rarely worth going to court over a few inches of garden, but if your neighbour starts to cultivate half your paddock, do not ignore it. "If you have occupied property for more than 12 years and no one has told you to buzz off, then you own it," says Crossley. And if you spot that next door's extension is being built over your garden, tell him to stop it at once. Do not wait until the building is finished, then ask him to knock it down; you'll have missed your chance, and will be estopped (a legal term meaning to hinder or bar).

If there is a boundary problem, don't inflame the situation by going straight to law. Says Powell, "You say to your solicitor, `my neighbour has moved the fence'. He takes you at your word, sends a nasty letter to your neighbour, who sees his solicitor; and two years later you end up in court. Get a chartered surveyor experienced in boundaries to do an initial appraisal and to advise you whether to forget it or to go for a full survey. The Law Society has a list of expert witnesses." Expect to pay about pounds 100 for the appraisal and about pounds 500 for the full survey.

If you have a case, take the survey report to a solicitor, who should then write politely asking the neighbour to return the boundary to its original position, or arrange a meeting to discuss the situation. "Eight times out of 10 this solves it."

Judges encourage parties to boundary disputes to settle out of court. And, if expert witnesses cannot reach agreement before the case is heard, some have their own means of forcing a settlement. Says Powell, "One judge said, `Before we go any further I must tell you that I am minded to make you each pay your own costs whatever the outcome'. The lawyers were furious but they went out, reached an agreement, came back in and told the judge they had settled. `What a surprise,' said the judge."