Chatham House, a hugely influential think tank, has released a worrying report about the vulnerability of the world’s nuclear stations.
They claim that the risk of a "serious nuclear cyber attack" is growing - and that we are frighteningly unprepared.
This is primarily because of ageing infrastructure, which has caused our online systems to become insecure.
Cyber criminals and terrorists are all increasing their online activity, the report continued, which means that the risk of a significant online-based attack is "ever present".
And, in some cases, nuclear systems in the UK could be breached with “nothing more than a flash drive”.
This is particularly worrying, as even a minor attack on a nuclear power plant could see deadly radiation released into the atmosphere.
“Even a small-scale cyber security incident at a nuclear facility would be likely to have a disproportionate effect on public opinion and the future of the civil nuclear industry,” the report said.
The current threat level for international terrorism for the UK is assessed to be "Severe".
There is only one threat level higher than Britain's current classification, dubbed "Critical", which means a terror attack is expected "imminently."
This means a terrorist attack directed at the United Kingdom is "highly likely.”
However, speaking with the BBC, Chief Executive of the Nuclear Industry Association Keith Parker said: “Security, including cyber security, is an absolute priority for power station operators."
"All of Britain's power stations are designed with safety in mind and are stress-tested to withstand a vast range of potential incidents.”