The Court of Appeal has ruled - but only by a majority - that the fairness of a dismissal must be judged solely by what those responsible for the decision knew (or ought to have known) at the time, even if crucial facts which could have exonerated the employee were known to another member of staff.
The principle that what matters is what is in the mind of the decision maker can work in the employee's favour, for example where further misconduct only comes to light after the decision to dismiss has been taken. But here it produced a harsh result: unknown to the dismissing officer and the appeal panel the misconduct for which the employee was dismissed was provoked by a racially-motivated remark by his line manager. However the full story did not emerge until an employment tribunal hearing two years later.
Of course the dismissal would have been unfair if the employer had not carried out a reasonable investigation before deciding to dismiss. But in this case the tribunal concluded that the employer could not be faulted on how it had approached things, though it might have been better for all concerned if the investigation had unearthed the full facts.