In an earlier article, some years before the Brexit Referendum, I examined the current ‘architecture‘ of the British state, in particular the way in which governmental power was distributed among the nations of the United Kingdom. The theme of this chapter was to show how the continuing (and, as James Bryce argued, inevitable) tension between centripetal and centrifugal forces could be usefully applied to power relations between the various nations of the United Kingdom, and between these nations and Europe, providing a basis for analyzing how these nations are drawn or impelled by some forces towards a centralized unitary polity, whilst at the same time other forces tend towards dispersion of power. The resulting pattern, I suggested, might then be analyzed along a spectrum from centralisation to independence, with subsidiarity, devolution and federalism being seen as weigh stations along the way. In this paper, I will reflect on this analysis in the context of the Brexit Referendum and the negotiations and debates that followed it, and I shall suggest that Brexit‘s effects on the state architecture of the United Kingdom are unpredictable but potentially profound.