[1979]QB P. 56

PEARLMAN V GOVERNORS OF HARROW SCHOOL
"No Court or tribunal has any jurisdiction to make an error of  law on which the decision of the case depends. If it makes such an error, it goes outside its jurisdiction." Lord Denning M.R.

R v Hull University Visitor, ex p Page, Lord Browne Wilkinson clarified that,

"The mere existence of a mistake of law made at some earlier stage does not vitiate the  actual decision made; what must be shown is a relevant error of law, i.e. an error in the actual making of the decision which affected the decision itself."  [1993] A.C 682