Henderson & Co v Williams
Henderson & Co v Williams  1 QB 521
This is an authority for estoppel by representation.
D, owner of goods at a warehouse, was induced by F's fraud to instruct the warehouseman ('W') to transfer the goods to F. F then sold the goods to an bona fide purchaser ('P'). W then stated to P that he was holding the goods at P's order. When F's fraud was discovered, W refused to deliver the goods to P. P sued.
W, having formally acknowledged the transfer of title to P, was estopped from impeaching P's title. W's refusal to deliver was a conversion. Damages were assessed as the market value of the goods at the date of the refusal to deliver.