This paper relates the processes of strategic planning in London during the first decade of an executive Mayoral system to Doug Yates' thesis about the ungovernability of major cities and London's long history of conflict around metropolitan governance issues. Yates' thesis only partially fits the London case because a separate lower tier of lower tier of borough authorities carries the main responsibilities for actual service provision. This London case, does, however, exemplify the proposition that without effective fiscal autonomy in planning for infrastructure provision, the need to manage diplomatic relations with higher levels of government (and other funders) can divert city strategies from those appropriate to the needs of the mass of their own constituents/businesses. In London as in other national capitals, this tension is intensified by a symbolic importance that inhibits central government from taking a detached stance in relation to priorities of the city administration.Examination of the experiience of Mayoral Plans for London suggest that sheer complexity of relations and interdependences across a much extended, diverse and dynamic metropolitan region is also a major restraint on governability as far as strategic planning is concerned. An inability to face up to this complexity, particularly in relation to cross-border relations has -as much as the (diplomatic) obsession with the 'global city' priorities -so far proved a major obstacle to using Mayoral strategic planning as an effective means of steering change in the region, and addressing central issues affecting economic efficiency and residents' quality of life.2