In a speech at MI5 headquarters in London intended as a show of Western solidarity, Christopher Wray, the FBI director, stood by MI5 director-general Ken McCallum. Wray reaffirmed longstanding concerns about China’s financial espionage and hacking operations, as well as the Chinese government’s efforts to stifle dissent abroad. “We consistently see the Chinese government as the biggest long-term threat to our economic and national security, and by ‘our,’ I mean both of our nations, along with our allies in Europe and elsewhere,” he said. Wray. He told the audience that the Chinese government “is determined to steal your technology, whatever it is that makes your industry stand out, and use it to undermine your business and dominate your market.” Ken McCallum said MI5 was carrying out seven times as many investigations into China as it did four years ago and planned to “increase again” to deal with the extensive inference efforts that cut into “so many aspects of our national life”. “Today is the first time that the heads of the FBI and MI5 have shared a public platform,” McCallum said. “We’re doing it to send the clearest message we can about a huge common challenge: China.” McCallum said the Chinese government and its “stealth pressure around the world” amounts to “the most game-changing challenge we face. “This may seem abstract. But it is real and pressing,” he said. “We need to talk about it. We must act.” A spokesman for the Chinese embassy in Washington, Liu Pengyu, dismissed the Western leaders’ claims, saying in an emailed statement to The Associated Press that China “strongly opposes and combats all forms of cyber-attacks” and called the accusations baseless. “We will never encourage, support or condone cyber attacks,” the statement said. In a nod to current tensions between China and Taiwan, Wray also said during his speech that any violent takeover of Taipei by Beijing “would represent one of the most horrific business disruptions the world has ever seen.” Last week, the US government’s director of national intelligence, Avril Haines, said at an event in Washington that there was no indication that Xi Jinping, the Chinese president, was ready to take Taiwan by military force. But he said Xi appeared to be “pursuing the possibility” of such action as part of a broader Chinese government goal of reunification with Taiwan. After the appearance, Wray said he would leave it to others to question whether an invasion of Taiwan was more or less likely following Russia’s invasion of Ukraine. But, he said, “I have no reason to believe that their interest in Taiwan has waned in any way,” and added that he hoped China had learned what happens “when you overplay your hand,” as Russia put it. Joe Biden said in May that the US would respond militarily if China invaded Taiwan, offering one of the White House’s strongest statements of support for Taiwan’s self-rule in decades. The White House later sought to soften the impact of the statement, saying Biden was not outlining a change in US policy toward Taiwan, a self-governing island that China considers a breakaway province that should be reunited with the mainland. The embassy spokesman said the Taiwan issue is “purely China’s internal matter” and said that when it comes to issues of China’s territory and sovereignty, the country has “no room for compromise or concessions.” “We will strive for the prospect of peaceful reunification with utmost sincerity and efforts,” the statement said, although it noted that China “will reserve the option to take all necessary measures in response to the intervention of foreign powers.” The Associated Press and Press Association contributed to this report