Analysis – The historical context behind the WWII bombs discovered in Devon
Introduction
The unprecedented discovery of two WWII bombs in Devon on the same day has made national headlines and caused much local disruption.
The two devices were discovered on Wednesday morning in separate locations in Plymouth and Exmouth. 400m cordons were put in place and residents were forced to evacuate, before both bombs were successfully removed and destroyed at sea on Friday morning.
These incidents form the latest in a series of notable UXO finds in Devon over the last five years, including a 500kg German bomb in Plymouth in 2024, and a 1,000kg German bomb in Exeter in 2021.
With residents now being able to return to their homes, we explore the historical context behind these recent discoveries.
Historical context – Plymouth
Plymouth is one of the most strategically important ports in the United Kingdom. For at least six centuries it has been used as a base for naval operations, and since the late 17th century, it has been home to HM Dockyard Plymouth (HMNB Devonport), one of the largest naval bases in Western Europe.
The strategic importance of Plymouth meant it was one of the most heavily bombed cities in Britain during WWII.
Luftwaffe attacks against Plymouth began in June 1940 and continued intermittently until April 1944.
The heaviest bombing, known as the ‘Plymouth Blitz’, occurred in March and April 1941. 5No. major air raids resulted in more than 3,750No. houses being destroyed, and a further 18,398No. being seriously damaged.
In total, a recorded 2,612No. bombs were dropped on Plymouth over 59No. air raids.
Firemen hang a Union Jack on a lamp-post after a two night attack on Plymouth (Wikimedia Commons)
Analysis
The device discovered in Plymouth was an SC50 German bomb. It was found on a building site on Bath Road, in the heart of the city. This was one of the most intensely bombed parts of Plymouth.
The approximate location of the WWII bomb in Plymouth (Google Earth)
An analysis of historical records shows this central area of Plymouth was significantly bombed on the night of the 21st – 22nd March 1941.
Several High Explosive (HE) bombs were records as falling on and close proximity to Martin Street and Bath Street, at the location of the current building site.
Compiled bomb map showing HE bomb impacts in Plymouth, 21st – 22nd March 1941 (The Box, Plymouth)
Further HE bombs, Incendiary Bombs (IBs), and Unexploded Bombs (UXBs) were recorded as falling on and in the vicinity of the site over several subsequent raids.
This bombing resulted in significant damage to buildings on and in the immediate vicinity of the site. The scale of the damage is apparent on post-war historical aerial photography.
Post-WWII aerial photograph showing bomb damage, circled in red, 1947 (Historic England)
The extent of this damage would be likely to mask the impact of a UXB (i.e. in rubble and debris).
Historical context – Exmouth
Whilst not as strategically important as Plymouth, Exmouth was subjected to a series of small scale bombing raids between September 1940 and February 1943. These predominantly comprised ‘tip-and-run’ raids, where small numbers of bombers jettisoned their payloads on opportunistic targets.
Exmouth is located approximately 12km southeast from the city of Exeter, which was the second most heavily bombed place in Devon after Plymouth.
In the spring of 1942, the Luftwaffe launched a campaign of night bombing against Britain’s historic cities, known as the ‘Baedeker Raids’. In April and May 1942, Exeter was targeted in 4No. major raids. During these attacks at least 400No. buildings were totally destroyed and approximately 1,800No. houses were rendered uninhabitable.
The River Exe was used as a navigational aid by Luftwaffe aircrew, leaving Exmouth vulnerable to overspill from these raids. In total, 47No. bombs were dropped on Exmouth over 14No. air raids.
Analysis
The bomb in Exmouth was uncovered in the vicinity of Exmouth Marina during dredging operations.
Whilst the exact nature of this device is yet to be confirmed, it is reported to be approximately 3-4ft in length and 2ft in diameter. This is suspected to be a SC250 German bomb.
Looking at regional bomb maps for Exmouth, we see a much less intensely bombed settlement than Plymouth.
On this raid map a handful of bombs are recorded as falling within approximately 0.5km of the Marina.
Exmouth bomb raid map, 26th February 1943 (National Archives)
Further digging through ARP logs and regional census records has revealed an incident dating from the 25th February 1941, in which 3No. HE bombs fell in the vicinity of St Andrew’s and Victoria Road.
ARP entry (Devon Heritage)
These roads run adjacent to Exmouth Marina.
Exmouth Marina and the nearby Victoria and St Andrew’s Roads (Google Earth)
Bombs falling in docks and waterways were often missed, particularly at night. If a fourth bomb was dropped during this raid, it is quite possible that it could have fallen in the water and gone unnoticed.
Conclusion
It is estimated that 11% of all bombs dropped during WWII failed to detonate. When planning to develop a site in areas that were subjected to bombing during WWII, considering the potential hazard provided by UXBs is critical.
For sites within Plymouth, a detailed UXO risk assessment is always essential.
If you require input on the potential bombing hazard for a site, you can download a free Unexploded Bomb (UXB) risk map: https://zeticauxo.com/guidance/risk-maps/. These provide a high-level overview of whether there is likely to be a significant hazard from WWII bombing near your site.
If you require further assurance on the potential bombing hazard, or other sources of UXO, our free Pre-Desk Study Assessments (PDSAs) can help: https://zeticauxo.com/pdsa-request-form/
Alternatively, get in touch with one of our UXO specialists via: uxo@zetica.com or 01993 886682.
