Watch: The arms race in space explained

The head of Britain's Royal Air Force has warned that we we now face an unprecedented threat in space, which could have a devastating effect on the satellites we rely on for communication, internet, bank transfers and satnav. A defence source has told BBC defence correspondent Jonathon Beale, that Britain has already used a ground based system to jam or block the satellite communications of a hostile state. Beale explains there is now a new arms race going on in space. More on this story.