Telecommunications engineers told Radio 1 Newsbeat that they were threatened and harassed by people who thought they were working on 5G, which was wrongly linked to the coronavirus.
Allegations of any link have been called complete rubbish by scientists.
But the union and the union representing thousands of workers across the UK say they have reported about 120 cases of abuse.
Reports contain threats of extreme violence.
“We have in fact had cases where people have been threatened with stabbing, threatened with physical violence and in some cases threatened with murder,” said Andy Kerr, assistant secretary general of the Communications Workers Union (CWU).
CWU represents nearly 40,000 telecom engineers.
Andy says that most don’t even work on 5G – they maintain the network and play “a crucial role”.
“People are stuck at home – whether they want to look at their Peaky Blinders box or someone is isolated and they want to stay in touch with their families.
“The only way to do it is through the telecommunications network. Most importantly, it is the engineers who maintain the network, so it is there for all health and emergency services. “
The National Crime Prevention Agency has confirmed that there have been a series of recent criminal attacks and cases of criminal damage to telecommunications masts.
Newsbeat spoke to three engineers who asked that only their first names be used because they are afraid for their safety.
Mike, 28, from North Yorkshire.
Mike has been an engineer for nine years.
“The incidents range from people shouting abuses, to videos, asking us why we are setting up death towers, why we are going to fry everyone.
“We had objects thrown at engineers. Threats that they will come back with groups of guys and stab them. We have had people who threaten to shoot us if we do not leave.
He admits that they must be “more vigilant” in the exercise of their functions since the beginning of the abuse and harassment of the engineers.
“There is a lot of uncertainty, we have to keep a closer eye on what’s going on and who’s talking. “
Jake, 24, from Birmingham
“Everyone I’ve spoken to says they have problems.
“My team and I saw people shouting, ‘You kill everyone, stop putting 5G on.’ It makes us mostly comfortable and asks how we are key workers and why we do what we do .
“There is this worry every day when you get in the van that something could happen – but you just have to keep going and keep everyone safe while waiting.” “
According to West Midlands police, crimes “are taken very seriously because of the risk they pose to the public.”
Sam, 26, from Plymouth
Sam lives with his wife and two daughters and is currently setting up temporary sites across the UK for the hospitals in Nightingale.
“A member of the public decided to seize my truck because he thought I was working on 5G.
“I made small changes to the way I work. We remove our traffic signs from our vehicles and wear the unbranded company uniform.
“I know other engineers at sites that have been vandalized – and they set fire to masts and the cabins were destroyed.
“My family is worried. My wife is at home, harassing me day after day when I leave the house, to stay in touch and make sure I’m fine.
“I love my job and we help keep everyone, including emergency services, connected at this crucial time, so I couldn’t feel more valued as an engineer.”
It is worth saying once again that the scientists insist that there is no connection between the broadband network and Covid-19.
Olga Robinson is the BBC specialist in coronavirus and 5G conspiracy theories.
“Scientists say 5G and coronavirus are completely different things – as different as chalk and cheese – so you can’t get the virus using 5G.
“They also say that 5G cannot affect your immune system and make you more vulnerable because the radio waves used are not strong enough to damage your cells, body, or immune system. “
Why do people believe it if it is not true?
“I think what makes these conspiracy theories more believable is that we still don’t know much about the coronavirus,” says Olga.
She says the theories also rely on “so-called experts and use scientific terms to make it look very sophisticated.”
And Olga has some simple tips on whether what you’re reading is true.
“First, stop and think, don’t share immediately,” says Olga.
“Then check the source of this complaint. Who is this person, what group have you seen making the claim? “
In other words, don’t believe this message in your WhatsApp group from a friend of a friend claiming to have received an email from someone who received an email from a doctor.
“Read the claims carefully and investigate each one because there are so many half-truths going around on social media.
“And if you’re still not sure after all your Google searches and checks, just don’t share – it’s that simple. “