Mersey Dock is in charge of training and providing crane operator to companies in the carrier business. On one occasion one of Mersey Dock's operators who was let to a stevedore company caused injuries through his negligent operation of the crane. The contract between the stevedores and Mersey Dock provided that the crane operator was an employee of the stevedores.
The court found that the agreement as to the employment was inconclusive, unless there is a real transfer of employment, Mersey Dock remains the employer. Because the crane operators worked through Mersey Dock and were trained by Mersey Dock, Mersey Dock's whole operation was based on letting out crane operators, Mersey Dock cannot be said to have effectively transferred the tortfeasor's employment.
According to Lord Porter to determine who the employer is the court must ask who has the power to tell the operator the way in which his work should be conducted?