“ 49 Late notice of appeal 49(1) This section applies in a case where- (a) notice of appeal may be given to HMRC, but (b) no notice is given before the relevant time. 49(2) Notice may be given after the relevant time limit if- (a) HMRC agree, or (b) where HMRC do not agree, the tribunal gives permission. 49(3) … 49(4) … 49(5) … 49(6) … 49(7) … 49(8) In this section “ relevant time limit ”, in relation to notice of appeal, means the time before which the notice is to be given (but for this section).”
“If applications for extensions of time are allowed to develop into disputes about the merits of the substantive appeal, they will occupy a great deal of time and lead to the parties’ incurring substantial costs. In most cases the merits of the appeal will have little to do with whether it is appropriate to grant an extension of time. Only in those cases where the court can see without much investigation that the grounds of appeal are either very strong or very weak will the merits have a significant part to play when it comes to balancing the various factors that have to be considered at stage three of the process. In most cases the court should decline to embark on an investigation of the merits and firmly discourage argument directed to them.”