No special rule for public authorities in litigation
In the case of Secretary of State for the Home Department v Begum  EWCA Civ 122 the claimant was a Pakistani national aged 70. She had applied for leave to remain in the UK, her application had been refused by the Home Office and she had appealed. Her appeal was allowed under an old version of paragraph 276ADE of the Immigration Rules, which then permitted a person to remain who “has no ties (including social, cultural or family) with the country to which he would have to go if required to leave the UK”.
Unhappy with this outcome and — as with the more
whitenewsworthy case of Myrtle Cothill — unwilling to allow an old lady to live with her family in the UK, the Home Office appealed to the Court of Appeal. Permission was granted by the Upper Tribunal. However, the Home Office lawyers then forgot to lodge what is called an Appellant’s Notice. In procedural terms, the Home Office abandoned their appeal. This was in fact an oversight and three months after the deadline the Home Office lawyers eventually filed the notice. In order for the appeal to proceed, an extension of time would have been needed from the Court.
Giving the leading judgment, McCombe LJ refused to extend time and thereby killed the Home Office appeal. He agreed that there was “a relatively strong case that the Tribunals had erred” but held that there is no special rule for public authorities:
After hearing Mr Thomann’s helpful submissions, there was no doubt in my mind that if a similar mistake had been made by solicitors in a private law case, there would have been no question of an extension of time being granted. As Moore-Bick LJ said in Hysaj there is no special rule for public authorities and in this case there were no issues of importance to the public at large. 
The second appeals test was also considered relevant and McCombe LJ is highly critical of the Upper Tribunal for having granted permission to appeal in the first place:
While permission to appeal had been granted by the Upper Tribunal, I have grave doubts whether the case properly satisfied the second appeal criteria. Even if the appellant was right that the Tribunals below had reached erroneous decisions, the principles were in truth well known and the decisions, on this hypothesis, merely represented failures to apply those principles properly. No new or separate point of principle or practice arose on the proposed appeals at all. Moreover, there was little, if any, public interest in the appeal being heard. The decision in the case would have been no more than an illustration of the application of well-known principles to the facts of the present case. I would add that the case turned upon a version of the relevant Immigration Rule that is no longer in force. Hence it is, to my mind, impossible to identify how the present case satisfied the relevant test for a grant of permission to appeal in the first place. 
This is not a case from which either the Home Office or the Upper Tribunal emerges with much credit, the latter having in the opinion of the Court of Appeal probably wrongly allowed the appeal but then also wrongly granted permission to appeal.