This book frames several historical incidents of violent movement-countermovement conflicts within the concept of 'cumulative extremism'-- the mutually reinforcing dynamic of radicalisation that can develop between two or more antagonistic groups.

Drawing on several in-depth case studies, including the contests between British fascist and anti-fascist groups in the interwar period and from 1967 to 1979 and 1980 to 2000; the Troubles in Northern Ireland from the late 60s to mid-70s; and Islamist extremists and the far-right counter-jihad movement in Britain since 2009, this book presents the first in-depth academic analysis of the concept of 'cumulative extremism' and constructs a theoretical framework through which to assess its development.

This is a groundbreaking volume which will be of particular relevance to scholars with an interest in the extreme right, social movements, political violence and criminology. It will also be of interest to policy makers and to practitioners dealing with extremism and radicalisation, including youth workers, Prevent coordinators, community support officers and police officers.