Russian President Vladimir Putin is "trying to intimidate" the UK with sabotage, arson and cyber attacks on British streets, according to the former head of MI6.
Speaking on BBC Radio 4's Today programme, Sir Richard Moore said Putin was "keen to expand the battlefield" beyond the war in Ukraine by interfering against countries supporting Kyiv in ways that do not "cross the threshold into open conflict".
His comments came after the BBC revealed that Russia was behind arson attacks targeting property and a car linked to the prime minister.
Sir Richard said proxy attacks showed Britain needed to have a "discussion" about "the balance of resourcing for security and defence".
On Monday, two men were found guilty of conspiring to carry out arson attacks on property and a car connected to Prime Minister Sir Keir Starmer.
Prosecutors found the attacks were carried out in 2025 after a suspect was recruited online by Russian-speaking Telegram user "El Money" who promised him payment.
A BBC Panorama investigation uncovered evidence suggesting he is a 23-year-old Russian diplomat Evgeny Lyukshin, the son of a senior official who has been schooled in information warfare by spies and propagandists.
The BBC found that "El Money" offered Russian citizenship in return for other attacks, and glorified Putin in messages. Accounts based in Russian also spread spread disinformation on the motive for the attacks.
The government and intelligence services have not yet said the Kremlin was behind the incident, but Sir Richard commended the BBC's reporting and said "we shouldn't be surprised at all" if Russian involvement was confirmed.
He claimed Putin was under pressure over the war in Ukraine which meant he was "quite keen to expand the battlefield a bit" by using sabotage, cyber attacks and arson in the hope it would "disruptive, distracting and intimidating to those of us who are supporting Ukraine".
Sir Keir said in April that "the use of proxies by hostile states in this country is a growing concern and a real concern", and the UK must "deal with malign state actors".
Sir Richard, who left MI6 last year, said the UK should address the concern by "doubling down" on its support of Ukraine, improving cyber security and investing in "good intelligence" to disrupt Russia's activity.
"There is a criminal justice element" to tackling the threat, he added, saying "thugs" who were recruited online must "go down for a very long stretch" if found to have acted as proxies for hostile states.
It follows the resignations of Defence Secretary John Healey and Armed Forces Minister Al Carns last week, who quit the government over a dispute with Sir Keir over funding for the military.
Writing on X on Monday evening, Carns said the arson attacks and subsequent disinformation campaign showed the UK needed to rethink its approach to defence.
He said defence was "the thread underneath everything now" and the incidents showed "why resilience matters".
Conservative leader Kemi Badenoch also condemned the arson attacks and said "no one should face intimidation, threats or attacks because they hold public office".
She added: "Democracy is settled at the ballot box, not through fear or violence and definitely not through foreign interference from hostile countries."
