Liz Truss will say Emmanuel Macron’s recent trip to China was a “sign of weakness”, after the French president asked Beijing for support in ending the war in Ukraine. In the latest of a series of foreign policy interventions designed to encourage Rishi Sunak to take a tougher approach towards China, Truss will say in a speech that any attempts by western leaders to appease Xi Jinping would be a mistake. She is expected to urge the UK government to pile greater economic pressure on Beijing while the Chinese are “building up their armaments” and “menacing the free and democratic” island of Taiwan. In thinly veiled comments aimed at Macron, who recently returned from Beijing after asking Xi to bring Russia “back to reason” over the war in Ukraine, Truss will say in a speech on Wednesday that the free world must “get real about the threat from authoritarian regimes”. Xi and Vladimir Putin are “allies against western capitalism”, Truss will tell the Heritage Foundation thinktank in Washington. “That is why western leaders visiting President Xi to ask for his support in ending the war is a mistake and it is a sign of weakness. “Instead our energies should go into taking more measures to support Taiwan. We need to make sure Taiwan is able to defend itself. We need to put economic pressure on China before it is too late.” The attack on Macron is a step up from her comments during last summer’s Conservative leadership race when she declined to say whether Macron was a friend or foe. Truss will lay out suggestions for the UK to follow the approach of the US and the Netherlands in adopting technology restrictions on China, and repeat the push she made in Japan two months ago for the creation of an “economic Nato”. China, towards which Truss has taken a more hawkish stance than Sunak, is one of the few subjects where Tory MPs treat her with some reverence. Despite her interventions, Sunak resisted reclassifying China as a “threat” instead of a “challenge” in an update to UK’s national security strategy in March. During her speech on Wednesday, Truss will attempt to link a strategy for challenging China’s “state capitalism” with her own much-criticised economic agenda. Despite the infamous mini-budget that sent global financial markets into a spiral, the pound crashing and sparked criticism from renowned economic institutions, Truss will warn that the approach of Anglo-American individualism – low taxes, a small state and private enterprise – is being “strangled into stagnation”. She will lambast the rise in state spending as a proportion of national income from 36% to 47% in the UK and 29% to 35% in the US since the turn of the millennium. Downing Street declined on Tuesday to say whether Sunak supported a controversial comment said to have been made by Macron to reporters on the plane home after the three-day visit to China. Macron is alleged to have said about fears of a conflict over the future of Taiwan: “The worst of things would be to think that we Europeans must be followers on this subject and adapt ourselves to an American rhythm and a Chinese overreaction.” A spokesperson for Sunak said ministers “want to do everything we can to reduce tensions” between China and Taiwan, and added: “We have a clear interest in the peace and stability in the Taiwan strait.”