Well, one thing's very clear, that terrorism isn't just a threat which is external to Western countries. It's not simply a foreign menace that comes from overseas to strike our cities. It can and it does, as we now know, come from within our own countries and from inside our own populations.

One of the marked characteristics of the U.K. security industry as compared with defence is the lack of company scale. This can put our firms at a competitive disadvantage when it comes to big contracts.

I am sorry to be leaving the BBC. I have enjoyed a fascinating seven years at the corporation and am particularly proud to have played a small part in the development of the BBC's Global News services, BBC World Service and BBC World.

Well, one thing's very clear, that terrorism isn't just a threat which is external to Western countries. It's not simply a foreign menace that comes from overseas to strike our cities. It can and it does, as we now know, come from within our own countries and from inside our own populations.

Those who say that the West and Islam are eternally irreconcilable have more in common with the Islam extremists than they might like to think, for it's the very same argument of course advanced by Al-Qaida. And they do have it wrong. We need to work with mainstream Islam.

The Internet plays an ever more significant role in the sedulous promotion of terrorism. We know that in the U.K., groups gather to view the preaching of violent men located many thousands of miles away and that this does have a powerful effect on young minds.

We owe it to the victims of the suicide bombers who struck London on 7 July 2005 to find out how the attacks happened and to learn the lessons that will spare lives in the future.