The common duty of care under the Occupiers’ Liability Act owed only to visitors. But a claimant’s status as “visitor” to the premises generally is necessary but not sufficient for there to be a duty in a particular case. So it’s always worth examining a bit further to see whether the common duty of care really was owed at the time of the accident.
Sometimes a person’s licence to enter premises is determined, and they stop being a visitor thereafter. So a drinker who sneaks back into a pub having been chucked out does so as a trespasser, as in Dobbs v Mitchells & Butler plc (Unreported, 5th December 2007).
Under Section 2(2) the duty is restricted to “the purposes for which (the visitor) is invited or permitted by the occupier to be there”: so, famously, “when you invite a person into your house to use the stairs, you do not invite him to slide down the banisters” (The Calgarth,  P 93 at 110).
There may also be a restriction as to where the visitor is entitled to go. Visitors may well not be entitled to wonder free all round the premises: the licence may well be limited. A person is only a lawful visitor to those parts of the premises where such visitors could reasonably be supposed to go in the reasonable belief they are entitled or invited to be there. So in the old case of Lee v Luper  3 All ER 817, a hotel guest was not a visitor when he stepped through a door marked “private”. And in a recent case involving this blogger, a wedding guest going through a door marked “staff only”, out of nothing more than idle curiosity, was not a visitor when he did so.
The question of a claimant’s status as visitor is more complex than simply whether the claimant was an invitee when he entered. So if there’s any possibility of doubt as to the claimant’s status as visitor, it’s always best to bring the case under the 1984 Act in the alternative, just to be on the safe side. And as a defendant, it’s usually worth taking the point!