Frustration may also occur where a change in the law or state intervention renders performance illegal. A classic example is where war breaks out, and to continue performance would mean trading with the enemy, as in Fibrosa Spolka Akcyjna v Fairbairn Lawson Combe Barbour Ltd [1943] AC 32, where a contract for the sale of machinery to be shipped to Gdynia was frustrated when that port was occupied by the enemy during World War II.