Britain has carried a series of covert attacks on Russia’s leaders and their allies, the former cabinet secretary has disclosed. Mark Sedwill said the UK had sought to exploit Moscow’s “vulnerabilities”, including through the deployment of its recently declared offensive cyber-capability. He said the aim of such actions had been to “impose a price greater than one they might have expected” in response to aggressive Russian behaviour. “Russia is operating in what the aficionados call grey space, that gap between normal state relations and armed conflict, with cyber-attacks, information warfare and disruption campaigns,” he told Times Radio. “It is important that we are capable of manoeuvring in the grey space and doing so effectively. We can’t leave the initiative to our adversaries. “There are vulnerabilities that we can exploit too. We just don’t always talk about them.” Lord Sedwill, who was also national security adviser until he stepped down last month, said the measures included actions against some of the “illicit” money flowing out of Russia. He said the occasions when the government took such action included the 2018 Salisbury poisoning of the former Russian intelligence officer Sergei Skripal and his daughter Yulia using the novichok nerve agent. “We seek to impose a price greater than one they might have expected when we believe it is right and necessary,” he said. “It does break through from time to time. After the Salisbury attack, the first use of chemical weapons against a country in Europe in a century, we retaliated in visible ways. We expelled the entire Russian intelligence network in the UK. “But we also took a series of other discreet measures, including measures tackling some of the illicit money that flows out of Russia, and covert measures, which obviously I can’t talk about as well.” His disclosure comes after a highly critical report in July by the parliamentary Intelligence and Security Committee said the government had badly underestimated the threat from Russia. The committee said ministers were “playing catch-up” and needed to take immediate action to counter Russian actions.