The former head of MI6 has voiced concerns that incoming president Donald Trump will not be able to grasp the complexities of the cyber era as tensions in this arena between the world's biggest nations continue to mount.
Speaking on a BBC Radio 4 documentary The New World: Axis of Power Sir John Sawers, who led MI6 between 2009 and 2014, said the world is returning to a phase of great-power rivalry between the USA, China and Russia not seen since the end of the Cold War.
As such there is a risk that suspicion and misunderstandings over cyber attacks and hacking could spiral out of control because the ground rules are not clear.
"We've not had a major cyber attack [like] 9/11, but you can't rule out something like that in the future," he said.
"One of the big problems we face with cyber is that it hasn't really been discussed internationally, about what is an acceptable use of cyber powers and where are the red lines and what happens when those red lines are crossed," he went on.
"We're at a very early stage. It's a bit like with nuclear weapons back in the 1950s. We've got the capabilities, but there are no rules lined up as to how they should be used," he said.
"China, the US and Russia feel more vulnerable to being attacked than having the power of being able to attack so this makes everyone err on the side of caution, but it's not based on an understanding of each others' capabilities. There's no hotline to say 'this is getting out of hand'."
Sawers said he was worried that recent developments on the international political stage did not bode well for fostering understanding.
"I'm not sure, frankly, that president Trump will be very well suited for having these discussions at the highest level."
Sir John's comments come at a time when the US intelligence agencies have accused Russia of hacking the Democratic National Congress's systems, releasing emails by Hillary Clinton's campaign chief John Podesta which may have swung the result of the presidential election.
Whether or not this is the case, Dmitri Trenin, director of the Carnegie Moscow Center, told the programme that the temptation to interfere using hacking will always be there.
"In an adversarial world if you can get away with something you do it", he said. "For Putin it's a way of getting back at Hillary Clinton's condemnation of Russia's own elections in 2011. He was very critical of US involvement in that campaign."
Sawers agreed with this assessment: "Putin is using cyber and propaganda warfare to assert himself in a way we haven't seen Russia do since the 1970s."
Sawers also said countries need to be wary of the technology around online voting, despite the obvious appeal to younger voters who are used to doing everything online.
"The younger generation of people expect to be able to do things remotely and through electronic devices," he said. "Bizarrely, the stubby pencil and piece of paper that you put your cross on in the ballot box is actually much more secure than anything which is electronic."
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