Arneil v Paterson
House of Lords (Scotland)
Citations:  AC 560; 1931 SC (HL) 117; 1931 SLT 399.
A statute made people strictly liable if their dogs injured cattle. Two dogs, owned by separate people, jointly attacked a flock of sheep and injured several of them. The sheep’s owners brought an action for damages under the statute. However, they only sued one of the dog owners.
That dog owner argued that they should only be liable for half of the damages. This was because there was no evidence as to which dog inflicted which injuries.
- Could one of the dog owners be held liable for the whole damage caused by both dogs acting in concert?
The House of Lords held in favour of the sheep owners. The law treated two dogs acting together to cause an injury as each responsible for the whole of the damage. As such, both dog owners were joint and severally liable for the whole of the sheep owners’ loss.
This Case is Authority For…
Where two causal agents act in concert to cause loss, and it is not clear to what extent the loss is attributable to each agent, the law assumes that both are responsible for the entire loss.