Guardian News and Media/London

David Cameron has declared that he wants to throw himself “headlong” into keeping Britain in a reformed Europe after countering “duff arguments” tabled by both sides in the EU debate.
As the prime minister prepared to unveil his EU reform plans in a letter to the European council president, Donald Tusk, today, he said he would campaign vigorously to remain in the EU if he succeeded in his negotiations.
Cameron was making a speech to the CBI annual conference in London yesterday when he was interrupted by students from the anti-EU campaign group Britain Affiliated, who were assisted by the Vote Leave campaign.
He mocked the students as they held placards and shouted: “CBI, voice of Brussels.”
As the students were led away by security guards, Cameron said: “We are going to have a debate. If you wait for a second you can ask me a question rather than interrupting what is a very good conference. Come on guys, if you sit down now you can ask me a question rather than making fools of yourselves by just standing up and protesting.”
The protesters stood up in the audience shortly before the prime minister talked about his EU reform plans.
Cameron said he would “debunk” two ideas promoted by the two sides - on the one hand, the anti-EU campaign’s argument that Britain could follow the example of Norway which has access to the single market but no say over its rules, and on the other, the pro-EU argument that Britain would be gravely damaged outside the EU.
Echoing language adopted by Boris Johnson, the prime minister said: “Today I also want to debunk an argument that is sometimes put around by those who say stay in Europe come what may. Some people seem to say that really Britain couldn’t survive, couldn’t do OK outside the EU. I don’t think that is true.
“Let’s be frank. Britain is an amazing country. We have got the fifth biggest economy in the world … The argument is whether Britain couldn’t survive outside the EU. Of course it could. The argument is how are we going to be best off. That is the argument I hope we are going to be making together after this successful negotiation.”
Cameron made clear that he would campaign enthusiastically to remain in the EU if his negotiations succeeded. He said: “When it comes to the crucial issues - our prosperity, our national security - of course we could try to look after those things outside the EU. But how would we make ourselves more prosperous and more secure? That is what the argument should be about. That is what I will throw myself into once I have completed this negotiation.
“I hope British business will back me in this negotiation because frankly the status quo isn’t good enough for Britain. We need to fix these challenges, fix these problems. That is what the negotiations are about and then we can throw ourselves headlong into keeping Britain in a reformed Europe. But as we do so, no duff arguments. No pretending Britain couldn’t survive outside the EU. Of course we could - the fifth largest economy in the world.”
The prime minister said he would seek to amend the Lisbon treaty to give Britain an opt-out from the EU’s commitment to forge an ever closer union of the peoples of Europe. But he declined to say that he was still committed to imposing a four-year ban on EU migrants claiming in-work benefits. Cameron simply said he was committed to the Tory manifesto which talked of imposing a ban “for a number of years”.
Cameron was followed by Enda Kenny, the Irish prime minister, who issued a heartfelt plea for the UK to remain in the EU.
The taoiseach said: “It is perhaps not surprising that Ireland regards the prospect of the UK leaving the EU as a major strategic risk. In truth, the full risks are unknown as much would depend on the detail of what a ‘Brexit’ process would actually look like. However, it is an outcome that the Irish government does not wish to see materialise at all.”