'52. In my assessment the fundamental principles to be derived from these cases and to be applied by tribunals where credibility is in issue may be summarised as follows: (1) there is no formal requirement that a claimant's evidence be corroborated – but, although it is not a prerequisite, corroborative evidence may well reinforce the claimant's evidence; (2) equally, there is no obligation on a tribunal simply to accept a claimant's evidence as credible; (3) the decision on credibility is a decision for the tribunal in the exercise of its judgment, weighing and taking into account all relevant considerations (e.g. the person's reliability, the internal consistency of their account, its consistency with other evidence, its inherent plausibility, etc, whilst bearing in mind that the bare-faced liar may appear wholly consistent and the truthful witness's account may have gaps and discrepancies, not least due to forgetfulness or mental health problems); (4) subject to the requirements of natural justice, there is no obligation on a tribunal to put a finding as to credibility to a party for comment before reaching a decision; (5) having arrived at its decision, there is no universal obligation on tribunals to explain assessments of credibility in every instance; (6) there is, however, an obligation on a tribunal to give adequate reasons for its decision, which may, depending on the circumstances, include a brief explanation as to why a particular piece of evidence has not been accepted. As the Northern Ireland Tribunal of Commissioners explained in R 3/01(IB)(T), ultimately "the only rule is that the reasons for the decision must make the decision comprehensible to a reasonable person reading it".'
'19. It will be an error of law to find a fact if there is no evidence to support that finding… Findings of fact which are challenged as erroneous for being against the weight of the evidence do not involve any error of law. It only becomes an error of law if the finding of fact is perverse in the sense that no reasonable Tribunal could have reached that conclusion. An example of such perversity would be where the fact-finding body proceeded upon a blatant misunderstanding or in total ignorance of an established and relevant fact. It must be established that the Tribunal acted upon a wholly incorrect basis of fact but that only arises where the fact is plain and incontrovertible and where there is no room for difference of view about it.'
'5. It cannot be overemphasised that there is no simple formula for writing reasons for a decision. The minimum requirements are that the unsuccessful party must know why his or her principal submissions have been rejected and that the process of the tribunal's reasoning must be sufficiently clearly outlined to avoid any reasonable suggestion that the tribunal have made an error of law. Obviously, the more clearly the reasons are expressed in the decision itself the better, but lack of clarity will not render a decision erroneous in point of law if the reasons can nevertheless be discerned with reasonable diligence from the decision and surrounding documents. A statement of reasons may be adequate even though it could have been improved … Those who assert that a tribunal's reasoning is inadequate must themselves explain clearly both the respect in which it is inadequate and why the inadequacy is of significance. It must be borne in mind that there are limits to the extent to which a tribunal is obliged to give reasons for reasons and to the extent to which they can be expected to give reasons for matters of value judgement. Furthermore, it is clear from R(A) 1/72 that it is not obligatory to deal with every piece of evidence and that, while "a decision based, and only based, on a conclusion that the total effect of the evidence fails to satisfy, without reasons given for reaching that conclusion, will in many cases be no adequate decision at all", that will not always be the case. What is required by way of reasoning depends very much on the circumstances of the particular case before the tribunal.'
'I desire to emphasise as strongly as I can that the fact that judge or commissioner does not set out every one of the reason which actuate him in coming to his decision will not be sufficient to support an argument in this court that he has not applied his mind to the relevant considerations… The mere fact that, in his judgment, the commissioner may not have mentioned some fact or other or that he emphasised some other fact is quite insufficient to persuade me that he did not, in fact, apply his mind properly to the relevant matters which he does not in terms mention.'