But I am an optimist about Britain; and the difference between an optimist and a pessimist is not that the optimist believes the world is wonderful and the pessimist believes it's beset by challenges; the difference is the pessimist believes we will be defeated by them; the optimist thinks the challenges can be overcome.

As the world transforms, moves closer together, jobs are displaced, and the world of work completely changes the way we live, the way we think. As that revolution goes on around us, it is going to pose political challenges of which immigration is one very obvious one, which are going to be extremely difficult to deal with. But it's like free trade. You know, in the end, if we go protectionist, we'll make a mistake.

I think social media is a revolutionary phenomenon all in itself.

After the terrible events of last week, there is still the shock and disbelief; there is anger; there is fear; but there is also, throughout the world, a profound sense of solidarity; there is courage; there is a surging of the human spirit.

The 21st century will not be about the battle between capitalism and socialism but between the forces of progress and the forces of conservatism.

My view always is that we should learn the lessons, both of the last sort of 50 years of policy-making and it is possible to get to a foreign policy that is engaged and active without going back to where we were in the post-9/11 world.

There are solutions that are proper, but they require the painstaking and difficult work of building alliances and also being prepared to analyze the problem realistically. And exactly the same thing is going on my side of the Atlantic as is going on your side of the Atlantic.