Per Sir W.Scott in The Gratitudine  EngR 525; (1801) 3 C Rob 240 at p.266:
… necessity creates the law, it supersedes rules; and whatever is reasonable and just in such cases, is likewise legal; …
Per Sir Montague Smith in Australasian Steam Navigation Co v Morse (1872) LR 4 PC 222 at p.230:
The word necessity, when applied to mercantile affairs, where meaning of the judgment must in the nature of things be exercised, cannot, of course, mean an irresistible compelling power. What is meant by it in such cases is the force of circumstances which determine the course a man ought to take. Thus, where by the force of circumstances, a man has the duty cast upon him. of taking some action for another, and under that obligation adopts a course which, to the judgment of a wise and prudent man, is apparently the best for the interest of the persons for whom he acts in a given emergency, it may properly be said of the course so taken that it was in a mercantile sense necessary to take it.