UK spy boss warns of threat of AI bioweapons

The head of Britain's intelligence agency, MI5, has warned of the growing threat posed by extremists and artificial intelligence. We hear from biological weapons expert Nikki Teran.
Also in the programme: Breaking Bad's casting director remembers RJ Mitte who has died aged 34; and the magnetic millirobots aiming to cure heart infections.
(Picture: Director General of MI5 Sir Ken McCallum speaking at Thames House, the headquarters of the UK's Security Service in London. Credit: Jonathan Brady/PA Wire)