On 25 November 1940, Agar was appointed chief staff officer to the rear admiral commanding Coastal Forces. This was a critical position as the Germans were vigorously attacking the coastal convoys running down the English Channel and up and down the east coast from Scotland to the northeast of England down to London. The threats were from aircraft, mines and fast German motor torpedo boats called E-boats. Britain had let her coastal forces deteriorate since the days when Agar had himself commanded CMBs.