Canada Steamship Lines Ltd v R [1952] UKPC 1, also referred to as Canada Steamship Lines Ltd v The King,[1] is a Canadian contract law case, also relevant for English contract law, concerning the interpretation of unfair terms contra proferentem.

[2] Although arising in civil law under the Civil Code of Lower Canada, it has been influential in similar cases under English law, but is now recognised as providing "guidelines" rather than an "automatic solution".

[1] In November 1940, Canada Steamship Lines Ltd (CSL) entered into a Crown lease for a twelve-year term, in which it became a tenant of certain dock property on which was situated a freight shed, on St Gabriel Basin on the Lachine Canal, part of the Port of Montreal.

According to proper practice he was negligent and should have used a hand drill because sparks flew and lit some cotton bales.

The Crown could realistically be said to have been strictly liable for damage to the goods (e.g. by breach of obligation to keep the shed in repair) and therefore negligence should not be covered.