The director of GCHQ, Jeremy Fleming, said he would encourage young people to use TikTok, despite a campaign pledge by the prime minister, Liz Truss, to “crack down” on the Chinese video app and companies like it. The spy chief was asked on Tuesday morning if he would be concerned if his children were to use TikTok after he had warned that China was seeking to “impose its values” in other strategic areas of science and technology. “No I wouldn’t,” Fleming replied, although he added that he would “speak to my child about the way in which they think about their personal data on their device” because people needed to understand that “there is no free good here”. Fleming said if personal data was used proportionally and “we’re happy with the way that data is safeguarded” then it should present no problem for consumers. As for the app in particular, he added: “Make the most of it, make those videos, use TikTok, but just think before you do.” Truss raised concerns about TikTok, owned by Beijing-based ByteDance, during the Conservative leadership contest in July, when she was asked during a TV debate whether she wanted to “crack down” on the company because of its Chinese ownership. “We absolutely should be cracking down on those types of companies,” Truss said in reply, although it was unclear what the then foreign secretary meant. China subsequently condemned her remarks as “irresponsible”. Truss is keen to pursue a harder line on China, and has reopened Boris Johnson’s integrated review of defence and foreign policy, with the expectation that Beijing will be formally declared an acute threat to the UK alongside Russia, as opposed to its current classification as a “systemic competitor”. Fleming will also raise concerns about China’s potential to manipulate technologies such as satellite location, digital currencies and the internet in a speech on Tuesday afternoon. Beijing’s efforts to exploit the control and surveillance capabilities in emerging technologies represents “a threat to us all”, he will say. But the spy chief believes that TikTok is unproblematic, reflecting an intelligence agency view that it does not pose a concern because the user data it harvests, like other popular apps such as Facebook, is not processed in China. Conservative sources say that Truss wants to push the agencies for an even firmer line on China, although despite her TikTok comments on the campaign trail it is unclear what this may mean. When Donald Trump was US president, he threatened to ban TikTok from the US but the efforts came to nothing and were abandoned by Joe Biden, who said threats posed by China-based apps should be evaluated through “rigorous, evidence-based analysis”.