An unexploded stash of 70 wartime grenades has been uncovered by power engineers carrying out routine maintenance.
The team from SP Energy Networks (SPEN) discovered the glass-bottled explosives – Home Guard phosphorous grenades from the Second World War – near Tongland Dam in Dumfries and Galloway this week.
The workers immediately contacted the emergency services and a 100-metre cordon was thrown around the site.
Bomb disposal experts carried out a controlled explosion on Wednesday.
Duncan Muir, team leader for SPEN in Dumfries, was in charge of the team on the ground.
He said: “The lads thought it was old milk at first when they saw the yellowed glass bottles, then one started slowly smoking and that’s when our health and safety training kicked in.
“We covered them back over with soil and retreated to a safe distance to call the fire brigade and the Ministry of Defence.
“The bomb squad were soon on site and knew exactly what to do.
“A 100-metre exclusion zone was put in place and we played our part in turning off the power supply in the immediate area to allow for a safe controlled explosion to be carried out.”
Residents from three nearby properties were temporarily evacuated and SPEN turned off the local power supply to a further 60 homes for a short time.
Mr Muir said: “I’ve worked for SP Energy Networks for almost 30 years and have never come across anything like this before.
“We’re carrying out a lot of work in the area to future-proof the network, upgrading transformers and installing new earth wire to improve the security of supply for our customers – all to support the country’s decarbonisation plans in the race to net zero.
“We certainly didn’t expect to come across something like this. It’s a first for me – and hopefully a last, too.”
The Home Guard was tasked with defending Britain’s coastline in the event of an invasion by Germany during the war.
The unearthed grenades were commonly known as the “SIP” (self-igniting phosphorus) grenade and were primarily to be used as an anti-tank weapon.
The Home Guard hid caches of these grenades during the war for use in the event of an invasion, but not all locations were recorded and some caches were lost.