D&S established negligence as a separate tort, and opened a gateway to future claims. Judges began to look for duty of care in cases depending upon their facts, and where this could be established compensation could be sought, provided of course that breach of that duty and damage could be shown.
Lord Aitkin gave his famous 'neighborhood principle' in D&S. He said that reasonable steps have to be taken towards acts or omissions that you can reasonably foresee would be likely to injure your neighbor.
This established where a minimum of the neighborhood test could be established, duty of care would be deemed to exist, and then its breach and the damage caused (which should not be too remote) would have to be proved to claim liability.
Duty of care was further expanded (its scope that is) in the case of Anns v. Merton. Here it was held that no existing precedent need to exist before a duty of care could be established. All that needed to be satisfied would be the neighborhood test, and any policy considerations or arguments against imposing a duty of care. Since the courts rarely touched upon policy matters, this 2-stage test became relatively simpler to satisfy and opened up possibilities for many future claims.
Junior Books v. Veitchi went another step further by stating that recovery for pure economic loss should also be allowed where the neighborhood principle could be satisfied, and no policy arguments against liability existed.
Murphy v. Brentwood however overruled Anns v. Merton and its 2-stage test and this was done mainly to stop the floodgates opening to everyone who wanted to claim for financial losses suffered by them. They (the courts in Murphy) stated that liability would only be imposed if the facts of the particular case were analogous to an existing precedent.
Caparo v. Dickman laid down 3 questions to be asked to determine a duty of care:
1. Was the damage to the plaintiff reasonable foreseen?
2. Was the relationship sufficiently proximate?
3. Is it just and reasonable to impose liability?
The last of these requirements deal with cases where liability should not be imposed. For example, where there is a statutory obligation to do something which has caused the damage, or in the case of doctors. To impose liability in such cases would mean that these professionals would not be able to do their work as efficiently, and thus lead to incompetence.
As Denning said...
"To impose liability on a Doctor would be like putting a dagger through his back."
Negligence extends to 3 main sub-topics. Negligence causing nervous shock, negligently said statements leading to economic loss, and negligently done acts leading to economic loss.
Nervous shock or psychiatric injury does allow the victim to claim provided that he/she satisfies the existence of a medically proven psychiatric injury, and satisfies the 3 Alcock requirements of relationship, proximity in time and space, and the manner of perception.
This is again to limit the possibility of opening the floodgates to too many future claims. Cases like King v. Phillips, where a mother could not claim injury to her child, as she was 70 yards away when the incident took place and thus considered not proximate enough in space.
So basically the effects of D&S have been extremely wide. Since its establishment as a separate tort, it has not only increased available remedies but also taken over a lot of other fields where it would not have applied before. Policy decisions and the need to limit the opening of floodgates have forced the courts to take retroactive steps and limit its scope. This by no means as correctly stated by Lord Macmillan closes the doors on future developments in negligence. Negligence claims and categories will develop depending on the facts and the situation in every individual case.