9.11.2017 A & Ors v Secretary of State for the Home Department [2004] EWCA Civ 1123 (11 August 2004) 224. I was not assisted by these repetitive arguments. It is axiomatic that a power of executive detention on grounds of no more than belief and suspicion – albeit reasonable belief and suspicion – is on its face grossly antithetical to established constitutional rights. Our task is to construe ATCSA Part IV so as to ascertain the nature of the power conferred by s.21, and by the same token the scope of SIAC's function under s.25(2). That requires some consideration of the policy and objects of the Act, to which I have already referred, and also as it seems to me the checks and balances for which, given the draconian powers of s.21, ATCSA itself provides: not only the right of appeal to SIAC but also the provisions for review in individual cases under s.26, the requirement for review of the operation of ss.21 – 23 under s.28, and the "sunset" clause provided in s.29. But we were not assisted by any developed submissions on these matters. 225. Mr Gill advanced two concrete submissions. The first was that where past facts are relied on by the Secretary of State to establish a reasonable suspicion that an individual is a terrorist within s.21, then on an appeal to SIAC the Secretary of State must prove the facts alleged "to a high degree of probability or at least on balance of probabilities". For this proposition Mr Gill relied on the decision of their Lordships' House in Rehman. The second concrete submission was that in assessing risk to national security under ATCSA s.25, SIAC should have paid less deference to the views of the Secretary of State (in essence, the views of the Security Service) than in fact it did. For this proposition Mr Gill sought to distinguish Rehman. 226. The passage in which SIAC address the question what deference is due to the Secretary of State's views on matters of national security is to be found at paragraphs 62 – 71 of the open generic judgment. I need cite only paragraph 67 (in which the references to Lord Steyn and Lord Hoffmann are to their Lordships' opinions in Rehman): "67. The question of whether a risk to national security exists is one on which the Commission should show deference to the Secretary of State. Due weight, not unquestioning adherence, must be given to the views and assessment of the Secretary of State who bears the direct responsibility for the safety of the country and is answerable to Parliament for his actions. As Lord Steyn said, at paragraph 28, 'the executive is the best judge of the need for international co-operation to combat terrorism…'. Lord Hoffmann made the point at paragraph 50 that the question of whether something is in the interests of national security is a matter of judgment and policy, entrusted to the executive and not to the courts. It is artificial to separate such issues from foreign policy, which is an issue for Ministers answerable to Parliament and not for the courts. At paragraph 54, he pointed to the need for the Commission to evaluate the material relied on by the Secretary of State, but considered that its scope to differ from the Secretary of State's views was limited by the advantage which he had over the Commission through the advice which he received from people with specialist day-to-day involvement in security matters, given the very considerable margin allowed to his appraisal of national security matters especially as they involved the assessment of risk. The cost of failure, as he put it, can be high; this required the judiciary to respect the conclusions of the Secretary of State that, in that case, support for foreign terrorists acting in a foreign country constituted a threat to national security. Such decisions required a legitimacy which could only be conferred by entrusting them to those who were answerable for them to Parliament." 227. Rehman was a case in which the Secretary of State had decided to make a deportation order against a Pakistani national under s.3(5)(b) of the Immigration Act 1971 on the ground that his deportation would be conducive to the public good in the interests of national security. Because of the national security element the appellant's appeal against the decision was to SIAC and not to the regular immigration appellate authorities; I need not give the legislative detail, which is contained in SIACA. SIAC allowed the appeal. The Secretary of State's appeal from SIAC was allowed by this court. The House of Lords dismissed the appellant's further appeal. 228. The reasoning in Rehman relied on by Mr Gill to support both arguments, namely that the Secretary of State must prove past facts relied on and that SIAC paid excessive deference to the Secretary of State's view of national security, is principally to be gathered from two passages, respectively to be found in http://www.bailii.org/ew/cases/EWCA/Civ/2004/1123.html 56/113