Former GCHQ Director Sir David Omand has said he believes the British public support the idea of the state monitoring communications in order to tackle and prevent terrorism and serious crime.

His comments came as the director general of MI5 Andrew Parker gave a speech in which he warned that thousands of Islamist extremists in the UK see the British public as a legitimate target for attacks.

Mr Parker said that despite huge investment over the past decade, the reality was that MI5 focused the most intense intrusive attention on only a small number of cases at any one time.