In Denton the Court of Appeal had an opportunity to recast the judgment in Mitchell.
Lord Dyson and Vos LJ said,
24 We consider that the guidance given at  and  of Mitchell remains substantially sound. However, in view of the way in which it has been interpreted, we propose to restate the approach that should be applied in a little more detail. 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” which engages CPR r.3.9(1) . 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)]”. We shall consider each of these stages in turn identifying how they should be applied in practice. We recognise that hard-pressed first instance judges need a clear exposition of how the provisions of CPR r.3.9(1) should be given effect. We hope that what follows will avoid the need in future to resort to the earlier authorities.
The first stage
25 The first stage is to identify and assess the seriousness or significance of the “failure to comply with any rule, practice direction or court order”, which engages CPR r.3.9(1)….
26 Triviality is not part of the test described in the rule… It seems that the word “trivial” has given rise to some difficulty…In these circumstances, we think it would be preferable if in future the focus of the enquiry at the first stage should not be…on whether the breach has been serious or significant… We recognise that the concepts of seriousness and significance are not hard-edged and that there are degrees of seriousness and significance, but we hope that, assisted by the guidance given in this decision and its application in individual cases over time, courts will deal with these applications in a consistent manner.
27 The assessment of the seriousness or significance of the breach should not, initially at least, involve a consideration of other unrelated failures that may have occurred in the past. At the first stage, the court should concentrate on an assessment of the seriousness and significance of the very breach in respect of which relief from sanctions is sought. We accept that the court may wish to take into account, as one of the relevant circumstances of the case, the defaulter’s previous conduct in the litigation (for example, if the breach is the latest in a series of failures to comply with orders concerning, say, the service of witness statements). We consider that this is better done at the third stage (see  below) rather than as part of the assessment of seriousness or significance of the breach.
28 If a judge concludes that a breach is not serious or significant, then relief from sanctions will usually be granted and it will usually be unnecessary to spend much time on the second or third stages. If, however, the court decides that the breach is serious or significant, then the second and third stages assume greater importance.
The second stage
29 The second stage cannot be derived from the express wording of CPR r.3.9(1), but it is nonetheless important particularly where the breach is serious or significant. The court should consider why the failure or default occurred: this is what the court said in Mitchell at .
30 It would be inappropriate to produce an encyclopaedia of good and bad reasons for a failure to comply with rules, practice directions or court orders. Para 41 of Mitchell gives some examples, but they are no more than examples.
The third stage
31 The important misunderstanding that has occurred is that, if (i) there is a non-trivial (now serious or significant) breach and (ii) there is no good reason for the breach, the application for relief from sanctions will automatically fail. That is not so and is not what the court said in Mitchell: see . CPR r.3.9 (1) requires that, in every case, the court will consider “all the circumstances of the case, so as to enable it to deal justly with the application”. We regard this as the third stage.
32 ….Although the two factors [(a) and (b) Ed] may not be of paramount importance, we reassert that they are of particular importance and should be given particular weight at the third stage when all the circumstances of the case are considered. That is why they were singled out for mention in the rule. It is striking that factor (a) is in substance included in the definition of the overriding objective in CPR r.1.1(2) of enabling the court to deal with cases justly; and factor (b) is included in the definition of the overriding objective in identical language at CPR r.1.1(2)(f) . If it had been intended that factors (a) and (b) were to be given no particular weight, they would not have been mentioned in CPR r.3.9(1) . In our view, the draftsman of CPR r.3.9(1) clearly intended to emphasise the particular importance of these two factors.
33 Our view on this point is reinforced by the fact that Sir Rupert recommended at para.6.7 of Ch,39 of his report that CPR r.3.9 should read as follows, including a factor (b) referring specifically to the interests of justice in a particular case:—
“(1) On an application for relief from any sanction imposed for a failure to comply with any rule, practice direction or court order, the court will consider all the circumstances including –
(a) the requirements that litigation should be conducted efficiently and at proportionate cost; and
(b) the interests of justice in the particular case.”
This recommendation was rejected by the Civil Procedure Rule Committee in favour of the current version. In our opinion, it is legitimate to have regard to this significant fact in determining the proper construction of the rule…
34 Factor (a) makes it clear that the court must consider the effect of the breach in every case. If the breach has prevented the court or the parties from conducting the litigation (or other litigation) efficiently and at proportionate cost, that will be a factor weighing in favour of refusing relief. Factor (b) emphasises the importance of complying with rules, practice directions and orders. This aspect received insufficient attention in the past. The court must always bear in mind the need for compliance with rules, practice directions and orders, because the old lax culture of non-compliance is no longer tolerated.
35 Thus, the court must, in considering all the circumstances of the case so as to enable it to deal with the application justly, give particular weight to these two important factors. In doing so, it will take account of the seriousness and significance of the breach (which has been assessed at the first stage) and any explanation (which has been considered at the second stage). The more serious or significant the breach the less likely it is that relief will be granted unless there is a good reason for it. Where there is a good reason for a serious or significant breach, relief is likely to be granted. Where the breach is not serious or significant, relief is also likely to be granted.
36 But it is always necessary to have regard to all the circumstances of the case. The factors that are relevant will vary from case to case. As has been pointed out in some of the authorities that have followed Mitchell, the promptness of the application will be a relevant circumstance to be weighed in the balance along with all the circumstances. Likewise, other past or current breaches of the rules, practice directions and court orders by the parties may also be taken into account as a relevant circumstance.”