Britain has accused President Vladimir Putin of plotting to install a pro-Moscow leader as head of the government in Ukraine as he considers whether to mount an invasion against Russia’s neighbour. The Foreign Office took the unusual step of naming former Ukrainian MP Yevhen Murayev as a potential Kremlin candidate to take over in Kyiv. The move comes as Western allies stepped up warnings that Russia will pay a heavy price if the estimated 100,000 troops massed on the border launch any kind of incursion into Ukraine. In a statement, Foreign Secretary Liz Truss said the Russian plotting showed the lengths to which the Kremlin was prepared to go to undermine the government in Kyiv. “The information being released today shines a light on the extent of Russian activity designed to subvert Ukraine, and is an insight into Kremlin thinking,” she said. “Russia must de-escalate, end its campaigns of aggression …