This article explores how the British Conservative Party has dealt with the dilemmas arising from its pursuit of two increasingly discordant goals: delivering Brexit and maintaining the domestic Union. Drawing on interviews and analyses of parliamentary debates, we identify a resurgence in the 2016–2019 period of an older belief in a unitarist state, and a new form of pro-Union activism in policy terms. Against those commentators who depict Britain’s Conservatives as having abandoned their unionist vocation, we explore the coalescence of a more assertive and activist strain of unionist sentiment. But we also find a willingness among Conservatives at the centre to sub-contract thinking about non-English parts of the UK to ‘local’ political representatives such as the Democratic Unionist Party and the Scottish Conservatives, and a growing anxiety about how to handle emergent tensions between the competing priorities associated with delivering Brexit and maintaining the domestic Union.