Tarleton, an employee of Weetabix, did not know that he had a condition that caused his brain to malfunction when his blood sugar was low. He caused a series of accidents after driving while hyperglycemic. He was found liable at trial which he appealed.
- Was the appellant impaired to the extent that he could not be held responsible for his actions?
Leggatt held that the standard of care required of the driver was that which is to be expected of a competent driver unaware that he is suffering from a condition that impairs his driving. To impose an objective standard without taking his condition into account is strict liability, which is not acceptable in tort law. Aldous agreed, noting that Tarleton did not and could not know of his condition and how it would affect his driving, thus his actions did not fall below the standard of care.
Overturns the rule established in Roberts v Ramsbottom and states that the situation must be taken into account when considering the reasonable standards that must be met to avoid liability.