jats:p A range of new spaces of English planning have emerged in recent years. One new space of clear import is the sub-region. In this paper we seek to gain a better understanding of why sub-regional spaces emerge, how they are used and how planning functions through them. Drawing upon an analysis of three English regions and interviews with actors the paper identifies four types of sub-regional planning that highlight the relationship between accountable, legally sanctioned territorial spaces on the one hand and more informal, open and strategic sub-regional spaces on the other. Sub-regional planning provides an important if not critical strategic parallel to regulatory planning though the relationship between the two is characterised by complexity, contestation, experimentation and impermanence. Among other issues raised by this contemporary reworking of planning is the emergence of an accountability gap through the uncoupling of formal democratic processes embedded within territories and the more diffuse practices of strategic plan making. </jats:p>