What is the standard of care owed to an invitee by a store owner?

The plaintiff had come to the store to shop, as the defendant wanted her to do. She was clearly an invitee. The standard of care owed to an invitee by the defendant was as stated by Willes, J., in Indermaur v. Dames, [1861-73] All E.R. Rep. 15, at p. 21: "... With respect to such a visitor at least, we consider it settled law that he, using reasonable care on his part for his own safety, is entitled to expect that the occupier shall on his part use reasonable care to prevent damage from unusual danger, which he knows or ought to know. ..." He is not the insurer of the safety of the customer. He is not liable for "usual" danger, only "unusual" danger.