Sir Demis Hassabis is stepping down as head of Google's British AI lab DeepMind and will become its chairman, with Google's Koray Kavukcuoglu taking over day-to-day operations. The shake-up, announced on Wednesday, sent shares in Google-owner Alphabet down 5.5pc. Kavukcuoglu, formerly DeepMind's chief technology officer, moved from London to the US last year when he was made Google's chief AI architect, and Google's AI leadership team is now expected to be concentrated in Mountain View, California. Sebastian Borgeaud, leading a key coding effort at DeepMind, has already moved to the US, while other senior UK researchers once based in King's Cross, north London, have left the company. DeepMind was founded in London in 2010, and Google bought it for around £400m four years later. Hassabis will also become chief scientist at Alphabet and continue to run Isomorphic Labs. Google said his new role "allows him to put his full attention on actively shaping the future of AGI," referring to artificial general intelligence. In a note to staff, Hassabis said he decided "now is the right time" to hand over operational responsibilities. Kavukcuoglu's title will be "senior vice president of Google DeepMind," rather than Hassabis's chief executive role.