The moment you stigmatize a whole group of people - for example, Muslims - then, obviously, you make the decent, law-abiding Muslims feel as if they're under threat in some way or that their legitimacy, as members or citizens of society, is brought into question.

For me, 9/11 was a game changer. It altered my perception of the security threat we faced. I took the position that Britain should be shoulder to shoulder with the U.S. It was a big decision; I didn't take it lightly, or in ignorance of its consequences. It's a big commitment for a country to give, but I believed it was the right thing to do.

I don't concede it at all that the intelligence at the time was wrong.

You choose your own reality and you - social media then amplifies those conspiracy theories. So that's why I say social media is itself a revolutionary phenomenon.

The purpose of terrorism lies not just in the violent act itself. It is in producing terror. It sets out to inflame, to divide, to produce consequences which they then use to justify further terror.

I learnt a lot in government, and I've learnt a lot since leaving government. The kind of journey of being in government is that you start at your most popular and least capable, and you end at your most capable and least popular.

People divide into groups where they talk to each other, but don't talk across the divide. And yet most of the challenges we face in the world today are challenges that are to do with trade, with technology, with how you make sure that people are properly educated, reform your health care system.