"The EAT's discretion to allow a new point of law to be raised or a conceded point to be reopened should be exercised only in exceptional circumstances, for compelling reasons, especially if the result would be to open up fresh issues of fact which, because the point was not in issue, were not sufficiently investigated before the employment tribunal. There is a strong public interest in finality in litigation. The inexperience of a party's advocate is not a sufficient reason to allow new points to be raised, or conceded points to be re-opened. Nor is the importance of the point to be raised. If any court or tribunal exercises its discretion in a particularly unusual manner, it is bound to give reasons. In the present case, the EAT gave no reasons for exercising its discretion in a way which seemed to run counter to established principles. Its ruling fell outside the range within which it could reasonably exercise its discretion and, accordingly, the appeal will be allowed, even though the effect would be to reinstate what is now known to be a wrong construction of law."