The effects of party expenditure on electoral outcomes can be analysed at a variety of levels, such as national and district. Using the example of Great Britain, where extensive research has been undertaken, this chapter illustrates that while the evidence for national-level expenditure effects is less conclusive, there is clear and consistent evidence that district-level spending delivers electoral payoffs. The chapter goes on to illustrate how national- and district-level spending has become increasingly integrated, such that the stand-alone national campaign no longer exists. Rather, its purpose is principally to support campaigns in the districts. This creates regulatory challenges, but without easy solutions. As a consequence, the chapter suggests that in spite of these challenges, regulatory changes in response to the increasing integration of campaigns may produce worse outcomes than the maintenance of the status quo.