The case arose out of a straightforward set of facts. A policeman, DS Neil Willan saw Ashley Williams dealing drugs in a park in the city centre in Huddersfield. DS Willan did not try and arrest him as he thought that he might run away. Instead, he called for back-up. DC Ian Green and DS Damian Roebuck then joined him and made the arrest. When they did so, Mr Williams resisted and there was a struggle. Mrs Robinson was passing by and the men collided with her and fell on top of her. She raised proceedings for damages for personal injury primarily on the basis of the negligence of the officers.
The Court of Appeal considered the famous test in Caparo Industries v Dickman  2 AC 605 and held that there was no proximity between Mrs Robinson and the police officers, notwithstanding the fact that she had been injured when they fell on top of her. It was not, according to the Court of Appeal, sufficient that there was a reasonably foreseeable risk of her being injured in the course of them carrying out the arrest. The Supreme Court over-ruled the Court of Appeal's decision and made a finding of negligence on the part of the police. The important aspect of the case, however, is the basis on which it did so.
Lord Reed begins his decision by explaining that the test in Caparo is misunderstood. There is no single test that applies to all claims in the modern law of negligence. On the contrary, the point of Lord Bridge of Harwich's judgement in Caparo was to "expressly repudiate the idea that there is a single test which can be applied in all cases in order to determine whether a duty of care exists" (para 21). Lord Bridge was proposing an incremental approach which used established authorities to provide guidance on how novel questions should be decided or duties or care could arise.
Accordingly, while in the majority of cases, the courts will be able to follow the general principles set out in Caparo the courts also "have to exercise judgement when deciding whether a duty of care should be recognised in a novel type of case" (para 27) like Robinson. When doing so, the court must remember that it is engaged "in a search for justice, and this demands that the dispute be resolved in a way which is fair and reasonable and accords with notions of what is fit and proper" (para 27).
For these reasons, Lord Reed makes clear that what the court is doing (and what Caparo does) is achieving a balance between legal certainty and justice. He continues that "in the ordinary run of cases, courts consider what has been decided previously and follow precedents (unless it is necessary to consider whether the precedents should be departed from). In cases where the question whether a duty of care arises has not previously been decided, the courts will consider the closest analogies in the existing law, with a view to maintaining the coherence of the law and the avoidance of inappropriate distinctions. They will also weigh up the reasons for an against imposing liability, in order to decide whether the existence of a duty of care would be just and reasonable." (para 29)
This is obviously an important clarification of the law and means that while Caparo will remain relevant in the majority of cases the court's focus, particularly in more novel cases, will often be much wider.