This book presents cutting-edge analysis of one of the most significant constitutional crises in recent British history: the prolonged and intense struggle between government and parliament for control over Brexit. It argues the crisis was very largely caused by the emergence of an Executive-centric approach to governance it dubs 'Whitehall Plus', and the strong parliamentary-push back it both provoked and responded to.

The book shows how the crisis exposed and widened deep fault-lines running through core doctrines and practices of the British constitution – profound disagreements long held unresolved and in abeyance, but which exploded into high-octane conflict during the period.