GCHQ head: Extremists use tech firms as 'control centres'

The new director of the intelligence agency GCHQ has accused technology companies of being "in denial" about the misuse of the internet by extremists.

Robert Hannigan has written in the Financial Times that major websites are being used as "command and control networks" for terrorism, and has called on them to work more closely with the intelligence services.

Richard Lister reports.