2U.K.Deprivation of life shall not be regarded as inflicted in contravention of this Article when it results from the use of force which is no more than absolutely necessary:
(a)in defence of any person from unlawful violence;
(b)in order to effect a lawful arrest or to prevent the escape of a person lawfully detained;
(c)in action lawfully taken for the purpose of quelling a riot or insurrection.