Prior to the ‘Blitzkrieg’ of May 1940, the risk of a German invasion of Britain was considered to be negligible. It was thought that any invasion fleet being assembled would be discovered by aerial reconnaissance, allowing it to be bombed and shelled to destruction before it reached Britain’s shores. Accordingly, all available Regular divisions were sent to France when fully mobilised, followed by Territorial Division when they became fit for service. Home Forces was reduced to a token force of semi-trained troops; in addition priority was given to France in the production of equipment, transport and artillery. As a consequence Home Defence, including the armament of “defended ports”, was far below that recommended.
During the first weeks of the War, German submarine activity off the North and West Coasts resulted in a decrease in the light Naval forces in the North Sea to provide protection for convoys. It was now considered that a German invasion fleet could slip through British Air and Naval patrols. The Commander-in-Chief, General Kirke, was asked to “prepare immediate plans to meet an invasion on a large scale, based on course of enemy action which had previously been ruled out as unlikely” – the resultant plan was known as the “Julius Caesar” Plan. General Kirke realised that the disembarkation of a Field Force was a slow formidable undertaking, even if carried out unopposed. He considered that German success would require the seizure of a port of considerable size, with the Humber and Harwich being the most likely targets. A key element of the JC Plan was to provide efficient infantry protection for the Fixed Defences, with particular emphasis on the Humber and Harwich.
Approaches to Harwich were limited by the Shipwash Bank and other banks and shoals situated between Shipwash Bank and the Coast. There are two channels to Harwich, the main one running NW from the Cork Sand Buoy then turning W to the Beach End Buoy. From there it ran N up the Harbour about 8,000 yards from shore. The second channel, known as the Medusa Channel, ran S from the Beach End Buoy past the Stone Bank Buoy.
Right: Approaches to Harwich
The scale of Harwich’s Fixed Defences can be seen in the table below. The Fixed Defences at Landguard, part of the Harwich defences, were the only Fixed Defences in place in Suffolk at the outbreak of the Second War.
Right: Harwich Fixed Defences
During the Invasion scare period of 1940-42, Harwich remained a major defended port, as it was within the area of the Wash to the Isle of White – the area considered most at risk to a full scale sea attack with fighter support. All the beaches in the area were considered suitable for disembarkation of enemy troops. However the Coast from Mill Bay to Harwich and Landguard Coastguard Station to Landguard Pier was under direct fire from the Fixed Defences. From Landguard Pier to River Deben, the Fixed Defences at Landguard could not sweep the beaches north of Cobbold’s Point any closer than 1,000 yards while Brackenbury with its counter bombardment role was ill equipped to deal with fast moving craft. This area was considered a possible weak point in the defences.
It was also one of the ports considered at risk by attack from modern battleships, battle cruisers and other ships of a lesser striking power. Brackenbury Battery had a Counter-bombardment role, but the 9.2” guns were considered inadequate against modern warships. Consequently, during 1941, a three gun 9.2” 35° battery was recommended to replace the current two 9.2” 15° guns but this was never implemented. However Landgaurd Right Hand Battery was upgraded with two 6” 45° equipments to allow it to also take on a Counter-bombardment role.
The Fixed Defences were under the command of a single Fire Command. Under conditions of good visibility, Batteries were not to open fire without orders from Fire Command. At night or under conditions of poor visibility, Batteries could open fire on any vessel on which they had received no previous information on. These general rules could be suspended in the event of a major Naval action in the area of if a large number of Destroyers were based temporarily at Harwich Port.
The Fixed Defences responsible for Counter-bombardment of Warships could expect support by gun or torpedo attack from Destroyers. An enemy Destroyer attack was to be tackled with Harwich’s Destroyer patrols, fire from the Fixed Defences to be withheld unless enemy vessels could be engaged without hampering friendly Destroyers. Any merchant navy vessel trying to get through the Examination Anchorage with hostile intent was to be stopped by the Fixed Defences.
During 1943 wireless communication was brought into use with sets at Fire Command, Landguard Right Hand, Manor House, Brackenbury, Bawdsey, Beacon Hill, and Cornwallis. Communication with Bawdsey was never satisfactory.