Sir Stephen Lovegrove said Britain had “clear concerns” that Beijing was expanding and modernizing its nuclear arsenal, adding that China’s “disdain” for arms control agreements was a “daunting prospect”. In a hardening of the UK’s position, Sir Stephen warned that the world may no longer have the Cold War safeguards that prevented nuclear war with the USSR and raised the prospect of an “uncontrollable conflict” between China and the West. He said the world was entering a “dangerous new era of proliferation”, with threats from genetic weapons, space-based systems and lasers. “We should be honest – strategic stability is at risk,” Sir Stephen said in a speech at the Center for Strategic and International Studies in Washington. “We have to start thinking about the new security arrangement.” It came as Liz Truss warned of China’s “malign influence” as she unveiled plans to build closer ties between the 56 nations of the freedom-loving Commonwealth. The Tory leadership candidate’s plan, announced as the Commonwealth Games begin in Birmingham on Thursday, will speed up the signing of trade deals between member states. “As one of the largest groups of freedom-loving democracies, we must ensure that there are clear benefits to remaining a member of the Commonwealth and offer nations a clear alternative to the growing malign influence from Beijing,” he said. Meanwhile, a leaked paper has cast doubt on her Tory rival Rishi Sunak’s claims that she is a China hawk. The Treasury document showed it was close to signing a new economic deal with Beijing earlier this year to make the UK the “market of choice” for Chinese companies. Mr Sunak has significantly hardened his line on China, describing it as the “biggest threat” facing the UK and pledging to ban Confucius Institutes in UK universities. He hit back at Ms Truss, highlighting comments he made when he was environment secretary in 2016 that relations with Beijing had “entered a golden age”. Joe Biden, the US president, is set to confront Xi Jinping, his Chinese counterpart, over Taiwan on Thursday in the pair’s first direct talks since March. Concerns are growing in Washington that Russia’s invasion of Ukraine may have persuaded Mr. Xi to try to seize Taiwan earlier than previously estimated.