This case is a reminder of the principles established in Jogee and Johnson & Others that to appeal on the basis of a change in the law out of time the Court of Appeal will need to be satisfied that there has been a substantial injustice .
For the reasons explained in Johnson at  and  there are powerful reasons why convictions properly returned under the law as it was understood at the time of conviction should not be set aside simply on that ground. This is why it is for the applicant for exceptional leave to appeal out of time to demonstrate that a substantial injustice would be done by refusing that application. As Mitchell makes clear, the continuing impact of a wrongful conviction on an application will be highly material in determining whether its continuation involves a substantial injustice. What follows in Johnson at  must be read with that in mind. This paragraph reads
“In determining whether that high threshold has been met, the court will primarily and ordinarily have regard to the strength of the case advanced that the change in the law would, in fact, have made a difference. If crime A is a crime of violence which the jury concluded must have involved the use of a weapon so that the inference of participation with an intention to cause really serious harm is strong, that is likely to be very difficult. At the other end of the spectrum, if crime A is a different crime, not involving intended violence or use of force, it may well be easier to demonstrate substantial injustice. The court will also have regard to other matters including whether the applicant was guilty of other, though less serious, criminal conduct. It is not, however, in our view, material to consider the length of time that has elapsed. If there was a substantial injustice, it is irrelevant whether that injustice occurred a short time or a long time ago. It is and remains an injustice.”
That paragraph expressly contemplates a situation with which the court in Johnsonwas concerned, namely people who had been convicted of murder having voluntarily decided to commit some other crime jointly with the principal offender, “crime A”. It is identifying the factors relevant to determining whether a substantial injustice would occur if leave were refused in that class of case and, no doubt, murder cases generally. In that situation it is unnecessary to consider what the continuing impact of the conviction on the applicant is, or how long ago it occurred. This is because they had all been convicted of murder and were subject to life sentences. In many cases they were still detained, but even if they had been released the impact of a life sentence is highly significant. If that sentence had been imposed on someone who was not guilty of murder this would clearly be a substantial injustice and that would be so whenever the sentence had been imposed. Those applicants were all therefore in the situation ofMitchell which is why that citation appears in paragraph  of Johnson. It was not necessary for the court to consider what approach might be required in a case where the sentence had long since been served and where the success or failure of the application could have no practical consequences.