A tort is a civil wrong, independent of contract, for which the law gives a remedy. The most important tort for practitioners is negligence. To succeed, a plaintiff must prove four things:
- A duty of care was owed.
- The defendant breached the applicable standard of care.
- The breach caused the plaintiff's loss (factual causation: the "but-for" test).
- The loss was not too remote (reasonably foreseeable) and is compensable.
The duty of care originates in Donoghue v. Stevenson (1932) and its "neighbour principle": you owe a duty to persons so closely and directly affected by your acts that you ought reasonably to have them in contemplation.
Standard of care, the professional gloss: An engineer or geoscientist is held to the standard of a reasonably competent member of the profession exercising ordinary skill and care. It is not a guarantee of a perfect result, and it is not the standard of the most brilliant practitioner. It is the reasonable professional in the circumstances at the time.
A professional who follows accepted practice and exercises reasonable skill is not negligent merely because the outcome was poor. Liability turns on the conduct, judged against peers, not on hindsight.