John takes Mary for a romantic evening walk in Covent Garden and declares that a diamond he owns, which is in a vault in France, is now hers. One month later, without having received the diamond, Mary leaves John for another. Within a year, John has engaged himself to Jane, upon whom he also bestows the diamond. John and Jane spend their honeymoon in Paris and, while they are there, John ‘delivers’ the diamond to Jane. Mary sues Jane in England for conversion and asks that Jane be ordered to return the diamond to her. According to English law, the transfer of title by way of gift depends on delivery.1 Thus, since only Jane took delivery, she has title and Mary's claim will be dismissed. In French law, by contrast, property in a gift passes without delivery.2 As a result, Mary has title to the diamond and Jane is holding it unlawfully. The case turns exclusively on the choice-of-law question, ‘Which law should govern?’