May I make a bit of progress?
Let me take one immigration case by way of illustration. A claimant whose leave to remain was revoked because of his dishonesty challenged that decision in the High Court. He was granted permission to bring his judicial review despite exhausting the appeal process at the immigration tribunal. The challenge was eventually dismissed, but not before it was sent back to the upper tribunal. At that point, the judges, Messrs Lane and Ockleton, noted that
“it appears that permission was granted on grounds which had no merit, ought to have been withdrawn by their proponent, and do not seem to have been regarded as giving a reasonable prospect of success even in the granting of permission.”
That is just one illustration. To give a sense of scale, on average, there are 750 judicial reviews against the upper tribunal alone each year, the vast majority of which are immigration cases. The success rate is just 3.4%. For completeness as well as appeals on immigration, the upper tribunal also hears cases on administrative and regulatory matters—things such as social security tax and property cases.