The class was to see most of its service for shore bombardment (naval gunfire support, "NGS") role. During World War I, they operated off the German-occupied Belgian coast bombarding naval forces based at Ostend and Zeebrugge including the Zeebrugge raid. Erebus was damaged by a remote controlled explosive motor boat and Terror was torpedoed by motor torpedo boats.
Both ships were placed in reserve between the wars but returned to service in World War II, when they were again used to provide fire support to British troops.
Erebus participated in the invasion of Normandy June 1944 as part of Task Force O off Omaha beach.2
Douglas Reeman's 1965 novel H.M.S. Saracen is a fictional account of the service of an Erebus class monitor in the Mediterranean Sea in both World Wars.
Mason, Geoffrey. Gordon Smith (ed.). "HMS Terror – Erebus-class 15in gun Monitor". Naval-History.Net. Retrieved 6 April 2014. http://www.naval-history.net/xGM-Chrono-03Mon-HMS_Terror.htm ↩
Antony Beevor (28 September 2010). D-Day: The Battle for Normandy. Penguin. p. 81. ISBN 978-0-14-311818-3. Retrieved 10 February 2012. 978-0-14-311818-3 ↩