Firstly, English law does, in extreme circumstances, recognise a defence of necessity. Most commonly this defence arises as duress, that is, pressure on the accuseds will from the wrongful threats or violence of another. Equally however it can arise from other objective dangers threatening the accused or others. Arising thus it is conveniently called duress of circumstances.
Second, the defence is available only if, from an objective standpoint, the accused can be said to be acting reasonably and proportionately in order to avoid a threat of death or serious injury.
Third, assuming the defence to be open to the accused on his account of the facts, the issue should be left to the jury, who should be directed to determine these two questions: first, was the accused, or may he have been, impelled to act as he did because as a result of what he reasonably believed to be the situation he had good cause to fear that otherwise death or serious physical injury would result second, if so, would a sober person of reasonable firmness, sharing the characteristics of the accused, have responded to that situation by acting as the accused acted? If the answer to both those questions was then the defence of necessity would have been established."
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