When I first left university, I thought about going into the private sector. But I discovered when I went to interview that I could only have a career in the back office, or doing HR. The attitude was, "My dear lady, you cannot possibly think about going on the board.

Our work in Britain suggests that radicalization is driven by an ideology which claims that Muslims around the world are being oppressed and - and this is the key bit of the argument - which then legitimizes violence in their supposed defense.

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.

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.

When I first left university, I thought about going into the private sector. But I discovered when I went to interview that I could only have a career in the back office, or doing HR. The attitude was, "My dear lady, you cannot possibly think about going on the board.

To a considerable extent we are faced by a technology arms race with terrorists. The communications revolution has made it easier for terrorist groups to reach out to vulnerable individuals with their violent extremist ideology and propaganda. It has also facilitated fundraising, recruitment and training.

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.