“It is important to notice that the resolution of the question what is the reason or, if there is more than one, the principal reason for the dismissal is important not only in relation to subsections (1) and (2) of section 57 but also in relation to subsection (3) for the question in subsection (3) is whether the employer acted reasonably or unreasonably in treating it as a sufficient reason for dismissing the employee and it must refer back to the reason or the principal reason determined under subsection (1). As Lord Simon of Glaisdale said in W Devis & Sons Ltd v Atkins[1977] ICR 662 , 682-683, referring to the predecessor of the present legislation: “the employer must satisfy the tribunal that he acted reasonably in treating ‘it’ (i.e., the reason shown by the employer as the reason for the dismissal of the employee) as a sufficient reason for the dismissal. … The reference to ‘equity and the substantial merits of the case’ … merely shows that the word ‘reasonably’ is to be widely construed; but they in no way affect the proposition that what must be shown to be reasonable and sufficient is the employer’s action in treating the reason shown by him (the employer) as the reason for dismissing the employee.” ”
“… As a matter of law a reason could not reasonably be treated as sufficient reason for dismissing Mr Smith when it had not been established as true nor had it been established that there were reasonable grounds upon which the special committee could have concluded that it was true. Unless, therefore, the industrial tribunal had held that reason 1(b) was not treated by the council as the reason which the council treated as sufficient for dismissing Mr Smith or that it formed no important part of the reason which the council treated as sufficient for dismissing Mr Smith, I am of opinion that the tribunal erred in law”
“20. As for the authorities cited on final warnings, Elias LJ observed, when granting permission to appeal, that the essential principle laid down in them is that it is legitimate for an employer to rely on a final warning, provided that it was issued in good faith, that there were at least prima facie grounds for imposing it and that it must not have been manifestly inappropriate to issue it. 21. I agree with that statement and add some comments.”
“22. First, the guiding principle in determining whether a dismissal is fair or unfair in cases where there has been a prior final warning does not originate in the cases, which are but instances of the application of s.98(4) to particular sets of facts. The broad test laid down in s.98(4) is whether, in the particular case, it was reasonable for the employer to treat the conduct reason, taken together with the circumstance of the final written warning, as sufficient to dismiss the claimant. 23. Secondly, in answering that question, it is not the function of the ET to reopen the final warning and rule on an issue raised by the claimant as to whether the final warning should, or should not, have been issued and whether it was a legally valid warning or a ‘nullity’. The function of the ET is to apply the objective statutory test of reasonableness to determine whether the final warning was a circumstance which a reasonable employer could reasonably take into account in the decision to dismiss the claimant for subsequent misconduct. 24. Thirdly, it is relevant for the ET to consider whether the final warning was issued in good faith, whether there were prima facie grounds for following the final warning procedure and whether it was manifestly inappropriate to issue the warning. They are material factors in assessing the reasonableness of the decision to dismiss by reference to, inter alia, the circumstance of the final warning.”