Russia faces a “critical shortage” of artillery shells and Moscow’s ability to conduct ground operations in Ukraine is “rapidly diminishing” as a result, Britain’s armed forces chief has said. Adm Sir Tony Radakin, the chief of defence staff, told an audience at the Royal United Services Institute (RUSI) thinktank on Wednesday that the Kremlin had only planned for a short period to subjugate Ukraine, and has instead found itself embroiled in a conflict lasting nearly 10 months. “So, let me tell Putin tonight what his own generals and ministers are probably afraid to say,” the military chief said. “Russia faces a critical shortage of artillery munitions. This means that their ability to conduct successful offensive ground operations is rapidly diminishing. “There is no mystery as to why this is the case. Putin planned for a 30-day war, but the Russian guns have now been firing for almost 300 days. The cupboard is bare. Morally, conceptually and physically, Putin’s forces are running low.” The admiral’s statement is the latest in a line of similar assertions by western and Ukrainian leaders and officials, who have been counting the number of missiles fired against known stockpiles – although there has been evidence of Russia making fresh munitions as the war has gone on. Earlier this month, Mykhailo Podolyak, a senior adviser to the Ukrainian president, said he believed Russia had only enough cruise missiles for “two or three” more mass strikes against Ukraine – and its first batch of Iranian drones had all but run out. Russia is estimated by Ukraine to have begun the war with 900 Iskander missiles and was down to 119 at the end of November after using 829 and producing 48 despite economic sanctions. Experts, examining fragments of Kh-101 cruise missiles that landed in Kyiv, have concluded that some were made since the summer. However, Russia continues to blitz Ukraine’s infrastructure, knocking out power supplies for millions or forcing them to ration energy. Last week the country’s president, Volodymyr Zelenskiy, said half the energy network had been destroyed by successive waves of missile attacks that began on 10 October and have stretched the grid to its limit. Radakin also sought to argue that Britain had to support the US and be engaged in opposition to China because “the notion that you can separate security in Europe from security in the Pacific seems difficult” – and floated the idea that the UK could regularly deploy an aircraft carrier in the Indian and Pacific oceans. Europe, he said, could not easily afford to defend itself without the US, because of the size of the Pentagon defence budget. “It would cost Nato’s European nations more than $300bn over 10 years to match US current investment in our security,” he said. There was also an unorthodox attempt to defend Britain’s nuclear deterrent by half apologising for it. “There is something very British in our approach to having the bomb: mild embarrassment,” the military chief said, and went on to argue that the west’s “extended nuclear deterrent” had helped protect countries in eastern Europe.