The History of Unexploded Ordnance in the UK

This informal CPD article, ‘The History of Unexploded Ordnance in the UK’, was provided by Brimstone Site Investigation who are Explosive Ordnance Disposal (EOD) experts dedicated to the safe removal and disposal of Unexploded Ordnance (UXO) across the United Kingdom and around the globe.

The History of Unexploded Ordnance in the UK

When it comes to UXO in the UK, many people’s thoughts will go straight to German bombs. It’s hardly surprising, when our cities were decimated by more than 450,000 explosives dropped from enemy planes. We know that many of these failed to explode, leaving a considerable danger buried beneath the surface.

However, thousands of tons of unexploded ordnance came from allied action, military training and ordnance manufacturing, creating a more complicated history than you might expect.

Enemy Action in WWI and WWII

During the First and Second World Wars, the UK was heavily bombed by the German Air Force, resulting in large quantities of unexploded bombs scattered throughout the country. The areas that were most at risk from German bombing included docks, airfields, major cities, manufacturing sites and industrial centres. Some of the most densely bombed cities included Birmingham, Bristol, Coventry, Exeter, Glasgow, Liverpool, London, Plymouth, Southampton and Portsmouth.

In 1937, the Air Raid Wardens Service was set up and was responsible for reporting incidents, extinguishing small fires and investigating reports of unexploded bombs. Despite their best efforts to identify the presence of UXO following an air raid, often the damage caused by detonated bombs made it difficult, with many items of ordnance going undiscovered. Some of these unexploded bombs continue to pose a risk to the public today.

There are three main types of German bombs which are found in the UK:

• High explosive bombs were dropped in their thousands in WWII. Common variants include the 50kg, 250kg and 500kg bombs. There were also 1000kg and 1800kg bombs dropped, however, these were less common.
• Incendiary bombs were designed to cause fires. These were used extensively in World War II, often in a conjunction with high-explosive bombs.
• Parachute mines, also known as aerial mines or ground mines, were adopted naval weapons that were deployed by the Germans over land based targets. There were two main variants, the Luftmine A which weighed 500kg and the Luftmine B which weighed 1000kg.

While UXO finds of this kind are rare, they do happen!

Allied Action in WWI and WWII

German bombs are just the beginning of wartime UXO. In Britain, we manufactured our own ordnance for our wartime activities abroad, although much of it was put to use in this country in military training. Munitions were regularly tested in live fire exercises, simulating a realistic combat environment. These exercises continued after the war, with RAF Cowden for example acting as a live firing range right up until 1998!

Old training grounds or firing ranges are regularly investigated and allied UXO are discovered including:

• Grenades
• Mortars
• Projectiles (sometimes these are referred to as shells)
• Small arms ammunition (this includes bullets and cartridge cases)
• Rockets
• Landmines.

Other allied UXO items found include those from the Home Guard. The Home Guard was set up in 1940 as Britain's 'last line of defence' against German invasion. Members were usually men unfit or ineligible for front line military service or who were above or below the age of conscription. Due to the lack of available weapons and ammunition in 1940, they often improvised and made their own weapons, including ‘Sticky Bombs’ and ‘Self-Igniting Phosphorus Grenades’, also known as SIP Grenades.

Once the war had finished, these were sometimes abandoned or forgotten about. There were an estimated 6 million SIP grenades produced by the Home Guard during WWII, and these are still found now and again across the country!

The Dangers of UXO

Whether they’re German bombs or Home Guard SIP grenades, suspected items of UXO should also be treated as dangerous and dealt with by specialists. Items of UXO often contain unstable compounds which can become more sensitive over time and can detonate unexpectedly if disturbed.

We hope you found this article helpful. For more information from Brimstone Site Investigation, please visit their CPD Member Directory page. Alternatively, you can go to the CPD Industry Hubs for more articles, courses and events relevant to your Continuing Professional Development requirements.