Russian authorities were behind a "destructive" and "malicious" cyber-attack on Ukraine which then spread across Europe, the UK government has said.
Foreign Office Minister Lord Ahmad took the unusual step of publicly blaming the June 2017 attack on the Kremlin, warning that Britain would "not tolerate malicious cyber activity".
The NotPetya ransomware attack was dressed up as a criminal operation, but Lord Ahmad said there was evidence that the Russian government - specifically the military - was actually behind it.
Ukraine's financial, energy and government sectors were all targeted, but the bug's indiscriminate set-up meant it spread into Europe and even back to Russia.
“The attack showed a continued disregard for Ukrainian sovereignty. Its reckless release disrupted organisations across Europe costing hundreds of millions of pounds," Lord Ahmad said.
“The Kremlin has positioned Russia in direct opposition to the West yet it doesn’t have to be that way. We call upon Russia to be the responsible member of the international community it claims to be rather then secretly trying to undermine it.
“The United Kingdom is identifying, pursuing and responding to malicious cyber activity regardless of where it originates, imposing costs on those who would seek to do us harm. We are committed to strengthening coordinated international efforts to uphold a free, open, peaceful and secure cyberspace.”