Speaking at the conference in Birmingham, Mr Cameron said Britain's success at the London Olympics showed "something important".
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But Mr Cameron said the case for the UK was about "our future as well as our past".
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Prime Minister David Cameron said the UK would "never buckle" in the face of terror attacks.
Prime Minister David Cameron said her resignation was "the right decision", his official spokesman said.
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It comes after David Cameron said council houses should no longer be allocated "for life".
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Prime Minister David Cameron said the EU should concentrate on tightening up banks in other ways.
In a round of TV interviews in Mumbai, Mr Cameron said Britain welcomed Indian university students.
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Mr Cameron said eurozone leaders needed to take swift action to resolve the crisis over Greece.
Mr Cameron said UK security was threatened by radicalism that was "poisoning young Somali minds".
Prime Minister David Cameron said on Tuesday defence spending would fall by 8% over four years.
However, First Aberdeen's operations director Duncan Cameron said the change to drivers' overtime was small.
"I am a great supporter of marriage, " Cameron said in the House of Commons.
Mr Cameron said the exercise was an "exciting opportunity" to engage with the electorate.
Ms Cameron said the new legislation would require manufacturers to put the right information on labels.
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Cameron said Coulson was quitting because of the continuing pressures on him and his family.
Prime Minister David Cameron said "slashing taxes" would only make the UK's fiscal deficit worse.
The Prime Minister David Cameron said the investment showed the UK was "open for business".
Mr Cameron said there were landowners willing to work with communities, and others who were not.
Mr Cameron said the use of public funds had drawn criticism from some quarters.
Mr Cameron said there were a mixture of reasons for buy-outs by communities and crofting townships.
Mr Cameron said the rescue involved a number of British troops, none of whom was injured.
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Prime Minister David Cameron said the investment demonstrated that the UK is "open for business".
Prime Minister David Cameron said the plans for a benefits cap were "right and fair".
"He was extremely excited about the news and thrilled about what lies in store, " Cameron said.
David Cameron said the French action in Mali was "in our interests" and should be supported.
Mr Cameron said the coalition also needed to address youth unemployment, which was "much too high".
Asked about the welfare secretary's comments, Mr Cameron said: "He has my full support".
Mr Cameron said there was a "difficult balance" between publicising arrests and respecting the privacy of suspects.
It is worth looking at what Mr Cameron said he would be asking for on social policy.
Mr Cameron said there would have to be "political agreement" for the joint taskforce to be deployed.
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