Gregory v Piper  9 B & C 591
Trespass – Vicarious Liability
Gregory (G) owned a pub called the Rising Sun with a stable-yard in the back which could be accessed by a back gate through Old King’s Yard. Piper (P) owned the property surrounding Old King’s Yard and disputed G’s right to pass through the yard to his stable. P employed a labourer (S) to lay down a quantity of rubbish, consisting of bricks, mortar, stones, and dirt, near G’s stable-yard, in order to obstruct the way. Part of this rubbish rolled against G’s wall and gates, and G refused to remove it. G raised an action of trespass against G.
The issue in question was whether a master could be liable for the trespass which occurred as a result of instructions the master gave to another in his employment. P claimed he could not be held liable because he had instructed S not to let the rubbish touch the wall, and the fact that the rubbish resulted in a trespass of G’s property was due to negligence on S’s part.
A master is liable in trespass for any act done by his servant in the course of executing his orders with ordinary care. P was therefore liable for trespass as it was a probable and foreseeable result of the S‟s act which P had instructed S to do. The trespass was a necessary or natural consequence of the act ordered to be done by P, therefore making P as the employer liable.