Four years and six months into the Russia-Ukraine war, Moscow has plunged Britain into its crosshairs by delivering a chilling warning.Russia’s embassy in London accused the UK of 'deliberately opting for an escalation of the Ukraine crisis, while hypocritically professing a desire for peace' after it emerged that Britain was supplying attack drones to Kyiv. 'London’s actions will inevitably carry consequences for which it will have to answer,' the embassy cautioned in the startling statement.While Russia has been engaged in hostile behaviour towards the UK for years, the threat could signal the beginning of a new era of unmasked aggression.The opportunities for escalation are numerous, from ruinous cyber attacks and sabotage, to espionage and even assassinations on British soil.Such activity would not be unprecedented: Moscow conducted two poisoning operations in Britain of defectors – Alexander Litvinenko in London in 2006, and Sergei Skripal and his daughter Yulia in Salisbury in 2018 – while Russian hackers routinely target the UK.But the Kremlin could go even further, by pummeling British facilities in Ukraine, or by sending suspicious drones to loiter above major airports such as Heathrow, Gatwick or Glasgow Prestwick.Another scenario is that Vladimir Putin unleashes strikes on Britain, with long-range missiles or drones. While the Russian military certainly has the capacity, would the Kremlin chief risk triggering all-out war? Russian President Vladimir Putin chairs a meeting on board of a missile cruiser 'Varyag' in Russia's far eastern Sakhalin Region, Russia, August 12