Clark v Nomura International plc [2000] IRLR 766, QBD Burton J on 6th September 2000, case no 00/TLQ/0092.
an employer's decision not to pay a discretionary bonus to an employee who was under notice of dismissal was such a perverse exercise of that discretion that the employee was entitled to claim the bonus (in this case amounting to £1.35m) as damages for wrongful dismissal.
There is also a useful discussion of the legal detail of this case by counsel for the employee in Richard Lieper's notes on the 11 King's Bench Walk web site