Robin Niblett
Director, Chatham House

From an interesting start, this ended up being a very disappointing, even bewildering 45-minute half debate on 'foreign affairs'. The visit of the Pope to Britain as a question of national security? Roof insulation and roof solar panels as the answers to climate change? At times, it sounded like the leaders were indeed living in Little Britain. To be sure, Britain's position in the European Union brought out some passionate disagreement, as expected. And British engagement in Afghanistan correctly drew some sustained discussion.

But, to re-use the over-used phrase of the debate, let's 'get real'. Which country is driving the most profound structural political and economic change in the world today? China, and this was not discussed. Where are the principal external terrorist threats to Britain emerging from? Pakistan, and it did not get more than a passing mention. Which country might present the most difficult national security choice to a future British Prime Minister? Iran, and its only mention was in the context of Trident modernisation - hardly the first option the next Prime Minister will reach for should Iran's nuclear enrichment programme continue apace or even emerge into a nuclear weapons programme in the next parliament. And what of the Arab-Israeli conflict, which continues to poison politics and security in the Middle East as well as relations between much of the Muslim world and the West? Not worth a question.

The impression from the limited answers given during this foreign policy debate was that Britain has a choice between three sharp party leaders, who are pretty well-informed on international affairs. However each is more in agreement than they would like to admit on the international challenges facing the country and the responses that are available. The exception on this was between Nick Clegg and the other two leaders on nuclear policy.

They are competing to lead a country whose citizens have not been asked to consider the significance of the profound changes taking place beyond their borders. To the extent that they do, these appear remote, at best, or, otherwise, confusingly intertwined with matters of domestic policy - whether in the areas of policing, migration policy or energy policy. Helping British citizens understand the extent of their interdependence with the world beyond Britain's shores will have to be a principal task for the next government.