Government post-Brexit will face sustained and difficult challenges as the UK adjusts to its new situation. Yet these challenges risk being exacerbated by fundamental changes in UK political debate that are affecting the perceived legitimacy and effectiveness of the system and structures of government. These include erosion of the clear distinction entrenched for the last 150 years between political choices by elected representatives and impartial administration by the civil service; the disruption of traditional deliberative processes by digital and social media; and increased centralisation of decision-making in No. 10 Downing Street combined with inadequate scrutiny of that decision-making either by the Cabinet or by Parliament.

The centralisation of executive power reduces its perceived legitimacy across the UK, with devolved government in Scotland and Wales seen as contingent on the Westminster Parliament and Northern Ireland under control by central government. Fiscally, the UK has become the most centralised democratic country in the world. As government faces up to the challenge of unwinding membership of the legal and regulatory framework developed during 45 years of EU membership, it is vital that the UK's political structures restore their legitimacy and efficiency.

Necessary reforms start with greater transparency about how government really works today. A PM's Department should be created, separate from the Cabinet Office; senior appointments including the Chief of Staff and ‘Advisors’, as well as instructions from No. 10 to departments, should be subject to effective Parliamentary scrutiny. Legally entrenched structures are required to confirm that devolved powers cannot simply be overridden by the Westminster Parliament. Greater fiscal autonomy should be guaranteed to local government.

Finally, politicians should choose either to recommit explicitly to the original system whereby the civil service remains separate from politics and take steps to make it effective; or acknowledge the drift towards greater political control of the civil service and introduce safeguards to minimise political abuse, for example by taking steps to increase scrutiny of appointments and expenditure.