Questions were submitted via YouTube, txt and email from all over the world.
Mr Cameron...
insisted that the UK had some of the strictest controls on arms sales in the world;
attacked the Libyan regime's conduct as "unacceptable";
explained the rationale for spending cuts, noting that the NHS - the service most important to vulnerable people - had had its budget ringfenced;
argued that he was being tough-but-fair on banks;
promised to rebalance the economy towards manufacturing and exports;
re-link the UK to the fastest-growing economies in the world;
committed to simplify the tax and regulatory system;
said that cannabis was a dangerous drug connected to mental illnesses and that drug legalisation would only increase use and problems;
noted that Iran was a different case from other potentially nuclear-armed states because it has vowed to wipe another state (Israel) off the face of the planet;
promised UK troops would "come home" from Afghanistan as soon as that nation's own security forces were able to stop the nation becoming, again, a base for al-Qaeda or other terrorists;
rejected the idea that an in/out referendum would resolve the question of EU membership and said he wanted to change the EU but remain a full member;
defended the right of Wales and Scotland to continue to offer free tuition at universities but argued that fees will, for English universities, mean a better-funded, higher quality education in the years ahead;
repeated his promise to reduce net immigration from the hundreds of thousands to the tens of thousands;
said the Berlin Wall's fall in 1989 - "the year of liberation" - was the most important world event in his political development and continues to give him hope for the future;
identified climate change as the greatest challenge facing the next generation and global poverty as the greatest challenge of today.
CCHQ has just released this video, including a contribution from Ken Clarke in which he describes AV as a "reckless" change. The video ends with a very direct appeal from the Tory leader to every Tory member to get out and vote "no".