It is too late to lock the stable when the horse has been stolen

It is useless to take precautions after something has happened that could have been foreseen and guarded against. The French version is, ‘After the death, the doctor.’

‘When his father gave Tommy an air-gun as a birthday present, Miss Watson, who lived next door, suggested that a small boy should not have so dangerous a toy. After Tommy had shot Miss Watson’s cat, his father took the air-gun away from him. We do not know what Miss Watson said about this, but a very suitable remark would have been, ‘It is too late to lock the door when the horse has been stolen.’