On what grounds can the decision of an employment tribunal be appealed?

There are two grounds of appeal to the Employment Appeal Tribunal (EAT). Either the employment tribunal made an error in law in reaching its decision (ie it misunderstood the law or did not apply the law correctly to the facts) or the decision is "perverse". A perverse decision arises where the tribunal arrives at a decision to which no reasonable tribunal could have come on the evidence before it. Appeals on the grounds that the decision was perverse rarely succeed. An appeal to the EAT cannot take the form of a re-hearing of the original tribunal and witness evidence is very rarely allowed. The notice of appeal must clearly identify the point of law at issue or the particulars of the alleged perversity.