Using artificial intelligence to fight terrorism

At the end of a week when we've been looking at the development of artificial intelligence (AI), we examine how effective computers can be in tracking suspected sex offenders - or terrorists.

The head of MI5 told us this week that the terrorist threat is at its highest level since 9/11. Our security correspondent, Gordon Corera, has been hearing about one British company - founded by people with a background in government and intelligence - to see what its AI technology can do.