Defendant was doing work to the front of a house, next door to one occupied by X, blocking the main entrance to X’s house, so that they only left a dangerous alternative route.
Plaintiff, a visitor, was injured while using this dangerous alternative route, and HL allowed her claim of negligence against Defendant (minus contributory negligence since she had declined help on the route).
Owed a duty to all who might be expected lawfully to visit the house to take reasonable care to ensure that they were not exposed to danger.
Where Plaintiff was aware of the danger but, in all the circumstances, a reasonable person would have risked incurring it, the contractors were not absolved from liability either by giving a warning or by reliance on the respondent's knowledge.
In considering what a reasonable person would realize or would do in a particular situation, “reasonable” does not necessarily equal what the majority of people would have done.
It is irrelevant that Defendant would not have had a right to put up warnings/fencing along the dangerous route in X’s property since it was they who caused the initial danger by blocking the main entrance.