R (o.t.a. Gallaher et al) v. Competition and Markets Authority  UKSC 25, 16 May 2018, read judgment
UK public law is very curious. You could probably write much of its substantive law on a couple of postcards, and yet it continues to raise problems of analysis and application which tax the system’s finest legal brains.
This much is clear from today’s Supreme Court’s decision that notions of public law unfairness and equal treatment are no more than aspects of irrationality.
The CMA (then the OFT) were investigating tobacco price-fixing. Gallaher et al reached an early settlement with the OFT, at a discount of their fines. Another price-fixer, TMR, did likewise, but extracted an assurance from the OFT that, if there were a successful appeal by others against the OFT decision, the OFT would apply the outcome of any appeal to TMR, and accordingly withdraw or vary its decision against TMR.
6 other parties then appealed successfully. TMR asked and got its money back from the OFT relying on the assurance.
Gallaher et al tried to appeal out of time, and were not allowed to. They then turned round to the OFT and said, by reference to TMR: why can’t we have our money back?