"Assistance may be refused:

(a) if the request concerns an offence which the requested Party considers a political offence, an offence connected with a political offence, or a fiscal offence;

(b) if the requested Party considers that execution of the request is likely to prejudice the sovereignty, security, ordre public or other essential interests of its country." (Article 2) .

It is clear from the provisions of Article 2 that the potential decisions to be made on behalf of "the requested Party" in respect of matters falling within those provisions are decisions which have to be made by governmental authorities accountable to Parliament. Such matters involve the assessment of factors outside the competence of courts, or of prosecution authorities acting alone and without government direction or guidance.

As Lord Diplock said in Tzu-Tsai Cheng v Governor of Pentonville Prison [1973] AC 931 at p.946, when considering the restriction in section 3(1) of the Extradition Act 1870:

'The purpose of the restriction, as it seems to me, was two-fold. First, to avoid involving the United Kingdom in the internal political conflicts of foreign states. Today's Garibaldi may well form tomorrow's government. And, secondly, the humanitarian purpose of preventing the offender [presumably Lord Diplock meant "the alleged offender"] being surrendered to a jurisdiction in which there was a risk that his trial or punishment might be unfairly influenced by political considerations. As indicated by the inclusion of the second part of the restrictions [barring extradition where it is sought "with a view to try or punish him for an offence of a political character" it was suspicion of the motives of requisitioning states in seeking the surrender of fugitive criminals [presumably "alleged fugitive criminals"] who were political opponents of the government of that state which underlay both the requirements of [s.3(1)] of the Act."

Similar considerations apply to Article 2 of the 1959 convention.