  A more modern version of this theory was proposed by MacCormick (1977), who argued that a right-holder was the intended beneficiary of a specific share of benefit, rather than just being a generalised beneficiary of the rules. However, even with this amendment, it remains difficult to explain third party rights under contracts. Suppose X and Y enter into a contract which imposes duties on each of them with the intention that performance of these will benefit Z. According to the theory, Z must (conceptually) be a legal right-holder. But it is in fact an entirely contingent matter as to whether Z is or not. Some legal systems recognise Z as having rights in such a situation and others do not. In Britain, for example, Scots Law long recognised such rights under certain conditions, but English Law did not until the position was changed by statute in 1999.