By Tim Montgomerie
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Philantropist Melinda Gates was Guest Editor of this morning's Today programme and one of her special guests was the Prime Minister. Mrs Gates - with Microsoft billionaire Bill Gates - has helped lead charitable efforts in the developing world to control malaria and other preventable diseases. David Cameron told Mrs Gates that support for aid grew when the specific benefits were set out. He mentioned the thirteen million people vaccinated by UK aid last year and the twelve million people who benefited from anti-malaria bed nets. ConHome polling confirms Mr Cameron's view that support for the aid budget grows when the questions asked move from the abstract to the specific.

The PM also said that there were reasons of the head as well as the heart to back development spending. By fighting poverty and disease overseas we avoid mass migration, pandemics, climate change and terror, he said. Prevention is better than cure.