258. Assignment by employer of benefit.

Two types of benefit may be assigned by the employer under a building contract. First, he may assign the right to call on the contractor to carry out or complete the works. Such an assignment is invalid if the contractor's obligations depend to any extent on the particular requirements of the employer1, as may frequently be the case in contracts to build on a particular site, or in contracts which provide a mechanism for varying the scope of the works in accordance with those requirements. The benefit of such obligations is incapable of assignment. In practice, assignment of the