Cyber-attacks could turn elections into “tainted exercises” that undermine Western democracies, the foreign secretary will warn.
In a speech in Glasgow later, Jeremy Hunt will say that authoritarian regimes view democratic elections as “key vulnerabilities” to be targeted.
But he will stress there is no evidence of successful interference in UK polls.
Mr Hunt will also call for economic and diplomatic sanctions to be part of the response to attacks.
He will add that the government is expanding its network of “cyber attaches” – diplomats working with governments around the world to address the problem.
Russia, China, Iran and North Korea have all been accused of being behind various hacks and online campaigns in recent years.
Last year, the UK blamed Russia’s GRU intelligence agency for a number of high-profile cyber attacks, including the hacking of Democratic National Committee emails in the run-up to the 2016 US elections.
But Mr Hunt will say that as well as publicly shaming states involved in cyber-attacks, a “doctrine of deterrence” is needed – with the threat of economic and diplomatic counter-measures in response.
“Authoritarian regimes possess ways of undermining free societies that yesterday’s dictators would have envied,” he will say.
“For every example of publicly attributed interference, there have been others that never saw the light of day… the implications are profoundly disturbing.
“At a minimum, trust in the democratic process is seriously undermined. But in a worst case scenario, elections could become tainted exercises, robbing the governments they produce of legitimacy.”