The general principle:
Smith v Littlewoods per Lord Goff:
The common law does not impose liability for what are called pure omissions
Yuen Kun Yeu v A-G Hong Kong per Lord Keith
“No liability… on the part of one who sees another about to walk over a cliff with his head in the air and forbears to shout a warning”
Michael v Chief Constable of South Wales Police 2016
No liability on part of the police who failed to arrive in time in respect of a 999 call as this failure was an omission.
Lord Toulson: English law does not as a general rule impose liability on a defendant for injury or damage caused to a person as a result of the conduct of a third party.