In 2020, Army and Navy bomb disposal teams saw an increase in taskings of about 20% compared with 2019, responding to more than 2,700 incidents across the UK.
There has been little let-up so far in 2021. Forces News has reported on a number of incidents involving unexploded bombs discovered by members of the public that have resulted in emergency responses from the military.
But not all the devices that are discovered are the result of World War Two-era enemy attacks.
During the Second World War, defence planners in Whitehall faced the grim prospect of a Nazi invasion. To fend off the country's chances of falling into German hands, adventurous and sometimes strange plans were hastily made to give the nation every chance of survival.
This included establishing Local Defence Volunteers (LDV), later known as the Home Guard.
However, 81 years on from their formation and the putting in place of severe defence obstacles and positions, a global pandemic has led to more people taking up outdoor hobbies and activities.
According to military officials, this has driven an increase in discoveries of unexploded Second World War ordnance in countryside settings such as canals, fields and forests.
But where have these leftover bombs come from, and who put them there in the first place? Let's find out.
Churchill's Defensive Orders
Within a week of Winston Churchill becoming Prime Minister in May 1940, the Secretary of State for War, Antony Eden, established the LDV, later renamed the Home Guard.
Unexpectedly, the uptake of volunteers to this new domestic force was tremendous. Within just six weeks, the Home Guard boasted a membership of 1.5 million Britons.
These enthusiastic community members, many of whom had served in the First World War, were given one task above all others: defend these lands when the invasion came.
However, initially, the Home Guard was left without uniforms and had to depend on privately owned weaponry including large knives and petrol bombs – dubbed Molotov cocktails.
The situation improved by July 1940 when members of the Home Guard were issued with uniforms and weapons, including Enfield Rifles, Browning Automatic Rifles and millions of rounds of ammunition.
Over the following year, the Home Guard also took charge of six million SIP (self-igniting phosphorous) grenades. But this ordnance came with strict rules about stowage.
The SIP grenades issued to Home Guard units had to be stowed carefully, ideally underwater. Under no circumstances were they to be kept in homes or community buildings such as church halls or pubs.
This led to many caches of the explosive devices being held at easily reachable underwater locations such as ponds and canals.
Magnet Fishermen Catching More Than They Bargained For
While some people sit on riverbanks and reel in trout, others prefer something more mechanical in their fishing nets, opting for the contemporary craze of magnet fishing.
Magnet fishing sees enthusiasts using specialist magnetic equipment to unearth hidden treasures from Britain's numerous river and canal beds.
Like many hobbies, the activity has seen a significant upturn in new enthusiasts hoping to find historical items, with magnet fishing kits available online from as little as £12.
But more and more frequently, magnet fishermen are catching more than they bargained for.
In May this year, a Nottinghamshire man pulled a WW2-era hand grenade out of a river while magnet fishing. The police made the area safe, and experts destroyed the "Mills Bomb" within hours. It was the second unexploded device found at the location in as many weeks.
Chief Superintendent Ian Roberts of Nottinghamshire Police said: "The member of the public who found the grenade did exactly the right thing by calling the police immediately.
"The device was clearly very old and was rusted, but we responded quickly to ensure that it could be safely destroyed.
"I'd like to thank the attending police officers and our colleagues from the Army for their quick action to dispose of the device with minimal disruption to the public."
Still, if you think finding one rusty grenade in a riverbed is dangerous, just think of the Bank Holiday walkers enjoying a stroll through woodland in Nottinghamshire in May who stumbled upon a cache of 100 grenades.
Nottinghamshire Police had to call in experts from the military to deal with the find, which resulted in a controlled explosion later that day.
Why Are Explosives Being Found In The Countryside?
On 27 May 1940, the Home Defence Executive was established, a body charged with making the country as defendable as possible from a full-scale invasion like those seen in other parts of Europe.
Defensive efforts put into full swing included:
- The building of static coastline positions, including hedgehog defences, coastal artillery installations, barbed wire entanglements, minefields, scaffolding structures, and the dismantling or destroying of piers along the southeast coastline.
- In-land anti-tank stop lines, including the General Headquarters Line spanning Bristol in the southwest to East London and then north to York and the Taunton Stop Line securing the southwest peninsula from attack.
- The flooding of some marshlands.
- The construction of thousands of miles of anti-tank ditches and anti-tank barricades made of concrete.
The large anti-tank stop lines constructed to fend off advancing Panzer divisions were mainly situated along already established obstacles such as rivers, canals, railway embankments and cuttings. These countryside locations were a vital element of defending cities that were, in some instances, hundreds of miles away.
Did The Home Guard Hide Grenades?
The six million SIP grenades disseminated to the Home Guard throughout 1940 and 1941 were intended to be used in the event of a large-scale German troop and tank invasion.
The grenade could either be thrown by hand or fired via mortar. However, although deadly if ignited, trials with tanks suggested that they did little to stop advancing armour if men inside the vehicles had closed down their hatches.
The incendiary devices were filled with phosphorous and benzene and would detonate upon impact.
Yet, given the grenades came with strict instructions on how and where they could be stowed, hundreds of Home Guard units hid caches of the bombs in strategic locations. Once hidden, the idea was that Home Guard members and civilians could locate the weapons and use them against German units.
These locations were typically countryside in nature, away from larger towns and cities where today, it is more common to find WW2-era bombs.
Historians have made suggestions that some Home Guard units haphazardly lost track of where the highly explosive SIP grenades were stashed.
Has There Been An Increase In Bomb Finds?
In 2005, another large-scale SIP grenade discovery occurred in the Brecon Beacons.
A British Army explosives team had to assemble a sand-filled skip before the devices were destroyed under control by the experts.
Speaking at the time, Captain Mat Symons said that the grenades had been "issued in crates to the Home Guard during the war but were never used."
"After the war, the Home Guard, not knowing what to do with them, often buried them. As a result, they are still being found today.
"Because they were hardly ever used, there are a fair few left of them. They were chucking them in ponds - we have found them in all sorts of situations, including Bronze Age burial grounds."
Earlier this year, the Ministry of Defence said that military bomb units had seen an increase of 20% on callouts to discoveries of explosive devices, many of which were leftover from the Second World War.
Colonel Daniel Reyland, Commander 29 EOD&S Group and the lead for the UK military EOD teams, said:
"The increase in taskings started during the first lockdown and continued throughout the remainder of the year. We have put this down to people digging gardens they hadn't dug before, clearing attics and sheds they hadn't cleared before and going for walks in places they hadn't walked before, during lockdown. Whilst a significant increase, it was well within our capabilities that we deploy every single day of the year in support of the Police."