“[40] In Denton, the Court of Appeal was considering the application of the later version ofCPR Rule 3.9 above to three separate cases in which relief from sanctions was being sought in connection with failures to comply with various rules of court. The Court took the opportunity to “restate” the principles applicable to such applications as follows (at [24]): “A judge should address an application for relief from sanctions in three stages. The first stage is to identify and assess the seriousness and significance of the 'failure to comply with any rule, practice direction or court order' ... If the breach is neither serious nor significant, the court is unlikely to need to spend much time on the second and third stages. The second stage is to consider why the default occurred. The third stage is to evaluate 'all the circumstances of the case, so as to enable [the court] to deal justly with the application including [factors (a) and (b) in Rule 3.9(1)]” [41] In respect of the “third stage” identified above, the Court said (at [32]) that the two factors identified at (a) and (b) in Rule 3.9(1) “are of particular importance and should be given particular weight at the third stage when all the circumstances of the case are considered. [42] The Supreme Court in BPP implicitly endorsed the approach set out in Denton. That case was concerned with an application for the lifting of a bar on HMRC's further involvement in the proceedings for failure to comply with an “unless” order of the FTT [43] … The clear message emerging from the cases – particularised in Denton and similar cases and implicitly endorsed in BPP – is that in exercising judicial discretions generally, particular importance is to be given to the need for “litigation to be conducted efficiently and at proportionate cost”, and “to enforce compliance with rules, practice directions and orders”. …” “A judge should address an application for relief from sanctions in three stages. The first stage is to identify and assess the seriousness and significance of the 'failure to comply with any rule, practice direction or court order' ... If the breach is neither serious nor significant, the court is unlikely to need to spend much time on the second and third stages. The second stage is to consider why the default occurred. The third stage is to evaluate 'all the circumstances of the case, so as to enable [the court] to deal justly with the application including [factors (a) and (b) in Rule 3.9(1)]”