The head of MI5 says he will "never back off" from confronting threats from China as he revealed his officers disrupted a case linked to Beijing in just the past week. More broadly, Sir Ken McCallum said the number of people in the UK under investigation for "state threat activity" - also including from Russia and Iran - has jumped by 35% in the past year compared with the previous 12 months. He admitted he felt frustration at the collapse last month of a trial against two British men accused of spying for China, but he stressed that the Security Service had still successfully derailed the alleged espionage operation. With pressure mounting on Sir Keir Starmer over why the high-profile trial foundered, the director general of MI5 - choosing his words carefully given the controversy - confirmed that "Chinese state actors" pose a threat to UK national security "every day". Read more on the Sky News website: https://news.sky.com/ #SkyNews #BreakingNews #Sky SUBSCRIBE to our YouTube channel for more videos: http://www.youtube.com/skynews Follow us on Twitter: https://twitter.com/skynews Like us on Facebook: https://www.facebook.com/skynews Follow us on Instagram: https://www.instagram.com/skynews Follow us on TikTok: https://www.tiktok.com/@skynews For more content go to http://news.sky.com and download our apps: Apple https://itunes.apple.com/gb/app/sky-news/id316391924?mt=8 Android https://play.google.com/store/apps/details?id=com.bskyb.skynews.android&hl=en_GB Sky News Daily podcast is available for free here: https://podfollow.com/skynewsdaily/ To enquire about licensing Sky News content, you can find more information here: https://news.sky.com/info/library-sales