An overconfident and assertive China under President Xi Jinping and Communist Party rule risks making miscalculations on the international stage, including underestimating the resolve of the United States, Britain’s spy chief said on Tuesday.

The world’s intelligences, from Langley to Moscow, are grappling with the transformation of China into a superpower challenging the post-Cold War dominance of the United States militarily, economically and increasingly in espionage.

Beijing believes its own propaganda about Western frailties and underestimates Washington’s and the West's resolve, chief of the Secret Intelligence Service (SIS) known as MI6, Richard Moore said.

The risk of Chinese miscalculation through over-confidence is real, he added.

China has repeatedly hit back at Western criticism of its actions, saying that the path set by its Communist Party has lifted hundreds of millions of people out of poverty. It denies abuses in Xinjiang, says former British colony Hong Kong faces a security threat from secessionists, and accuses the United States of creating tension over Taiwan.

Moore, who joined MI6 in the 1980s and worked under diplomatic cover in Vietnam, Turkey, Pakistan and Iran, said technological progress over the next decade could outstrip progress over the past century.

Our adversaries are pouring money and ambition into mastering artificial intelligence, quantum computing and synthetic biology, because they know that mastering these technologies will give them leverage, Moore said.