Boris Johnson has warned that the UK must take “every possible precaution” to protect itself from Russian retaliation following the coalition air strikes on Syria.
The Foreign Secretary said Moscow had a track record of launching cyberattacks on infrastructure and interfering in the democratic processes of other countries.
His comments come amid concern that Russia may start a clandestine campaign of retribution, following the strikes by the US, UK and France on targets of the Moscow-backed Syrian regime.
Mr Johnson also revealed that contact between himself and Russian foreign minister Sergei Lavrov had gone cold amid the military operation, in which the Western coalition partners fired more than 100 missiles at facilities around Damascus.
The Cabinet minister said the operation would not make a material difference to the Syrian civil war and he could not say it would definitely stop the Assad regime from using chemical weapons again, but he argued that the strikes had sent a strong message that their use would not be tolerated.
Mr Johnson spoke to the BBC’s Andrew Marr Show as reports suggested British intelligence chiefs feared that Russia could retaliate with a “dirty war”, using cyberattacks and even seeking to smear figures in the British political establishment.
Asked about the possibility of “revenge attacks” that could target electrical or NHS systems, he said: ”You have to take every possible precaution, and when you look at what Russia has done, not just in this country, in Salisbury, attacks on TV stations, on the democratic processes, on critical national infrastructure – of course we have to be very, very cautious indeed.
“But I want to stress, we in the UK do not seek an escalation, absolutely not.”
News stories on Sunday suggested that since the Salisbury chemical weapons incident, which left ex-spy Sergei Skripal and his daughter poisoned by the novichok nerve agent, Theresa May had received intelligence that the Russian government could hit members of the UK establishment with “kompromat”.
When you look at what Russia has done, not just in this country, in Salisbury, attacks on TV stations, on the democratic processes, on critical national infrastructure – of course we have to be very, very cautious
Intelligence officers at GCHQ and the Ministry of Defence are said to be on stand-by to retaliate to any cyber warfare “proportionately”.
Asked about contact with his Russian opposite number Mr Lavrov, Mr Johnson said contact with the Russians had “not been good”, but explained that it had continued at a military level to ensure “deconfliction”, the clashing of coalition and Russian forces, and at the UN.
He said the UK and its allies had limited its action, because it did not seek an escalation in the war or with Russia, but he added: “I went to Moscow in December and we held out the hand of engagement. We want to engage with Russia.
“But I’m afraid the Russians give us every possible signal and evidence that we also have to beware.”
The UK’s role involved four Tornado fighters launching Storm Shadow missiles at a military facility 15 miles west of Homs.
Intelligence assessments suggested the Assad regime was keeping chemical weapons at the site, which Ms May said was a breach of Syria’s obligations under the Chemical Weapons Convention.
The US part of the operation used twice as much weaponry as the attack that Washington launched unilaterally last year, with missiles and planes hitting research sites.
France also targeted alleged chemical weapons facilities, after President Emmanuel Macron said the country had proof the Assad regime was involved in Douma – an incident that Mrs May has said left more than 70 people dead and hundreds needing medical attention.
But in his interview, Mr Johnson said he was under no illusions about what the operation would achieve, with Russian forces likely to have been warned in advance and the possibility that they may have informed the Assad regime of targets, allowing it to move chemical weapons stocks before the missiles were fired.
Asked whether he thought Assad still had some chemical weapons capability, the minister said: “I can’t answer that question. Clearly the strikes were successful on three important sites.
“But the overwhelming purpose, the mission, was to send a message, that after years now in which we’ve seen a series of chemical weapons strikes…finally the world has said ‘enough is enough’.
“I think it’s important to understand the limits of what we are trying to do…we must be honest. This is not going to turn the tide of the conflict in Syria. One can hope that it encourages the Russians to get Assad to the negotiating table in Geneva, to get a political process properly going, But that is, as it were, an extra. The primary purpose is to say ‘no’ to the use of barbaric chemical weapons.”