Squatters' rights - this is how to commit adverse possession on a piece of land which is not your own. Adverse possession is, of course, a euphemism for stealing. Morrissey was right, educated criminals do work within the law. Note that this only applies to plots of land in the UK and Ireland.
The first thing to note is that adverse possession is not an aggressive act, you do not acquire the other person's right of ownership, they give it up. It is a kind of careless abdication on their part. NB: this kind of theory does not apply to other areas of the law. You cannot get away with stealing someone's pint, for example, on the premise that they gave up their right to possession when they set it down on the bar without attaching a sticky label to remind everyone to whom it belonged. Although first year law students and most polytech students will occasionally fall for this.
So how do you dispossess someone of their land? There are two elements to this.
Firstly, you must show corpus possessidendum. This is actual physical control of the land. The quote is that you show corpus possessidendum when you "deal with the land in the way you would expect an occupying owner to deal with it" from Slade J in Powell v MacFarlane. There are infinite possibilities as to how you could do this:
Grazing the land is a good example, upheld in Powell v MacFarlane, Treloar v Nute, and grazing the land without paying rent is even better - Pye v Grahame.
Other good ones include levelling or landscaping your neighbour's land, erecting buildings, fencing or using his land as a garden for yourself. However, should you erect a fence one night to keep your neighbour off the land you intend to dispossess him of, only to have it removed the next morning, it doesn't count as good physical control (Marsden v Millar).
So, the best ways to dispossess someone of their land are to usher in a herd of bovine or ovine and let them graze away, or, if it's a building you want to legally pilfer, simply break in. And then change all the locks (this worked for the defendant in Mount Carnell Investments v Thurlow, so there's no reason why it shouldn't work for you!).
So, once you've got control of their land, what else do you need to do?
You need to show an intention to have exclusive control of the land, in other words, you have to assume the mantle of an adverse possessor. There are a number of ways to do this: you can write the owner a letter asserting your rights (Buckinghamshire County Council v Moran), or if it's a building, you can change all the locks, post a sniper on the rooftop, buy some rottweilers to guard it. Anything that says "this is mine now, stay away" to all and sundry, especially the true owner is legally valid.
So, now that you've taken physical control of the land, and asserted your will to be its new owner, what else do you need to do? Wait.
For at least twelve years. The Limitation Act 1989, Schedule 1 states that once the squatter is in place, the clocks starts ticking. There also accrues a right of action for the owner of the land. He can take an action for trespass, or an action for the recovery of the land. Or they can simply come round with a piece of paper which states that they own the property and get/incite/convince/blackmail you into signing it.
So if the owner of the land takes no action to stop your scheme, how long exactly must you wait before it's yours?
Well, this depends on who exactly owns the land. If it's an ordinary joe, we're talking twelve years: Limitation Act Art. 21(1). If it's a government minister, officer or any person acting on behalf of the Crown in right of Her Majesty's Government, you can expect to wait thirty years - Limitation Act Arts. 21(3) and 74 (3).
And if it's a piece of foreshore - the area of land exposed between high and low tides, you'll have to wait no less than sixty years. Although why on earth anybody would want to squat in such a ridiculous place for six decades is beyond the imagination.