Richard Barrett
Media playback is unsupported on your device
Video

Woolwich killing: 'Incredibly hard' to stop such attacks

Ex-MI6 counter-terrorism head Richard Barrett has told BBC Two's Newsnight programme that little can be done to stop attacks that need little preparation.

It follows the brutal killing of a soldier outside Woolwich Barracks on Wednesday.

He said the two suspects "probably didn't have any intention to commit a crime like this until relatively recently".

"When does a person who expresses radical views, who joins a radical group, flip over to over to be a violent extremist?

"To find the signals, the red flags as it were, I think is enormously hard."

  • 24 May 2013
  • From the section UK
Go to next video: Woolwich residents in shock over murder