P was made redundant and engaged as an IC, who had to arrange for a substitute if he was unwilling or unable to work, and could exercise this right of substitution at any time. CA held that P was not an employee because the right of substitution was inconsistent with the nature of a contract of service.
Peter Gibson LJ: The court must look to the actual facts only insofar as it is necessary to find that a clause might be a sham. However it is generally the rule that the courts will look to the rules of the contract rather than actual facts to determine whether P is an employee or not. A zero hour arrangement cannot be a contract of service. “It is necessary for a contract of employment to contain an obligation on the part of the employee to provide his services personally. Without such an irreducible minimum of obligation, it cannot be said that the contract is one of service.”