Private conversations of high-profile politicians and civil servants have been compromised by Russia’s principal security service during “sustained” attempts to interfere in UK politics, a Foreign Office minister has said.

Leo Docherty issued a statement in the Commons in which he said a cyber influence campaign by a group known as Star Blizzard, “almost certainly” a subordinate of an FSB cyber unit, had “selectively leaked and amplified information” since 2015.

Mr Docherty said the group had conducted an exercise known as spear-phishing to steal information from a “significant” number of parliamentarians from multiple political parties.

It is understood there are hundreds of victims of attempted hacks by Russia across the UK, many being widely recognisable names – with personal email accounts being targeted, not just official emails.

He added that impersonation attempts and “false accounts” had been made to compromise email accounts in the public sector and wider civil society to create a “believable approach seeking to build a rapport before delivering a malicious link”.

MPs were told sanctions would be imposed on two members of Star Blizzard following a National Crime Agency investigation, named by the Foreign, Commonwealth & Development Office (FCDO) as Andrey Stanislavovich Korinets, AKA Alexey Doguzhiev, and FSB intelligence officer Ruslan Aleksandrovich Peretyatko.

They have been targeting high-profile individuals and entities with a clear intent - using information they obtain to meddle in British politics

Mr Docherty said the Russian ambassador was summoned to the FCDO to be told “these actions have consequences”.

It is understood the ambassador was unavailable when summoned and officials instead met with a senior member of the Russian government to express concerns over the attempts to interfere in democratic processes.

Speaking about Russian “attempted cyber interference” and “malicious cyber activity”, Mr Docherty told MPs: “I can confirm today that the Russian Federal Security Services, the FSB, is behind a sustained effort to interfere in our democratic processes.

“They have targeted members of this House and the (House of Lords). They have been targeting civil servants, journalists and NGOs (non-governmental organisations).

“They have been targeting high-profile individuals and entities with a clear intent – using information they obtain to meddle in British politics.”

The minister continued: “We want to be as open as we can be with the House and the British public. Our commitment to transparency stands in sharp contrast to the efforts of the KGB successors to exert influence from the shadows.

“Centre 18, a unit within Russia’s FSB, has been involved in a range of cyber espionage operations targeting the United Kingdom.

“Secondly, that Star Blizzard, a cyber group the National Cyber Security Centre assesses is almost certainly subordinate to Centre 18, is responsible for a range of malign activities targeting British parliamentarians from multiple parties.

“Thirdly, using these means the group have selectively leaked and amplified the release of sensitive information in service of Russia’s goals of confrontation.”

In sanctioning those responsible and summoning the Russian ambassador today, we are exposing their malign attempts at influence and shining a light on yet another example of how Russia chooses to operate on the global stage

Following Mr Docherty’s statement in the Commons, Foreign Secretary Lord David Cameron said: “Russia’s attempts to interfere in UK politics are completely unacceptable and seek to threaten our democratic processes. Despite their repeated efforts, they have failed.

“In sanctioning those responsible and summoning the Russian ambassador today, we are exposing their malign attempts at influence and shining a light on yet another example of how Russia chooses to operate on the global stage.

“We will continue to work together with our allies to expose Russian covert cyber activity and hold Russia to account for its actions.”

The FCDO said FSB had been identified as being involved in the hacking of UK-US trade documents leaked ahead of the 2019 general election and the 2018 hacking of UK think tank Institute for Statecraft.

In December 2021, the account of the think tank’s founder Christopher Donnelly had been targeted by FSB, with documents subsequently leaked, the FCDO added.