CYteafer, [/# ABSTRACT Chester city walls have suffered throughout their life from continuing movement and by the late 1980's there was considerable concern for their stability. The paper describes the archaeological and engineering investigations, the knowledge gained on the structural history of the wall and the current causes for its instability. INTRODUCTION The Chester City Walls, are of international and historic importance, forming a complete circuit around the inner city. The walls have been adapted and developed throughout history in places preserving sections of the Roman fortress wall adjacent to and beneath medieval and Victorian construction.