In Devis & Sons v Atkins, the House of Lords rules that whether a dismissal is unfair must be judged according to the facts which the employer knew or should have known at the time the decision to dismiss was taken.
In C A Treganowan v Robert Knee & Co Ltd [1975] IRLR 247 HC, the High Court held that a clash of personalities between employees constitutes "another substantial reason" for dismissal within the meaning of the Trade Union and Labour Relations Act 1992.