Cassidy v Ministry of Health [1951] 2 KB 343 is an English tort law and UK labour law case concerning the scope of vicarious liability.

Mr Cassidy went to hospital for a routine operation on his hand, but came away with stiff fingers because of the negligence of one of the doctors.

[1] He attempted to sue the Ministry of Health in its capacity as employer.

The Ministry argued it could not be held responsible and had no vicarious liability, relying partly on Collins v Hertfordshire[2] where it had been suggested that a surgeon was not the 'servant' of his employer.

Denning LJ said,[1] The reason why the employers are liable in such cases is not because they can control the way in which the work is done - they often have not sufficient knowledge to do so - but because they employ the staff and have chosen them for the task and have in their hands the ultimate sanction for good conduct, the power of dismissal.He also noted,[1] that where a patient selects the doctor, then the doctor will not be employed by a hospital.