This, indeed, is one of the main justifications for the imposition of different forms of mandate by higher-level governments. Local authorities are likely to underspend on services or investments that generate benefits for the wider region (positive spillovers) and may be too ready to pursue development or other investment choices that generate negative externalities for their neighbours. Collaboration in such circumstances is one of the major reasons why public investment, in particular, may require a multi-level approach, with a degree of leadership from more senior levels of government (OECD, 2013c).