In my view, it is essential to be very careful before adding harassment claims to litigation about the proper position of the boundary between neighbouring properties.
Does the behaviour of the neighbour next-door really pass the threshold? Even then, is it worth the additional cost? If the claim is necessary pick just the clearest or worst examples. Make sure that the evidence supports the claim and that everything is properly thought through. Nothing will undermine a good boundary case more than presently an ill-judged harassment case to the same Judge. It would be easy for the Judge to use poor evidence on one to justify adverse findings on the other.
In Dowson v Chief Constable of Northumbria [2010] EWHC 2612 (QB) at [142], Simon J summarised the relevant principles which must be satisfied in a harassment claim:
(1) There must be conduct which occurs on at least two occasions,
(2) which is targeted at the claimant,
(3) which is calculated in an objective sense to cause alarm or distress, and
(4) which is objectively judged to be oppressive and unacceptable.
(5) What is oppressive and unacceptable may depend on the social or working context in which the conduct occurs.
(6) A line is to be drawn between conduct which is unattractive and unreasonable, and conduct which has been described in various ways: ‘torment’ of the victim, ‘of an order which would sustain criminal liability’.
Finally, with respect to (2), provided the course of conduct is targeted at someone it need not be targeted at the claimant, as long as it causes sufficient alarm and distress to the claimant as well (Levi v Bates [2015] EWCA Civ 206).
Harassment claim may of course arise in a free-standing way and need not be between neighbours or indeed related to boundary disputes. In practice however they frequently arise between neighbours.