Director General of Fair Trading v First National Bank plc
Director General of Fair Trading v First National Bank plc [2001] UKHL 52 is the leading case on the Unfair Terms in Consumer Contracts Regulations 1999. It was an action to test the fairness of clauses in loan agreements which secured a bank's commercial interest rates after a debtor that had defaulted and they had been to court to determine their repayment scheme.
Source: Wikipedia — Director General of Fair Trading v First National Bank plc (CC BY-SA 4.0)