From the BBC, we read more details about today's meeting.
He is co-chairing the first meeting of a United Nations panel, along with the presidents of Indonesia and Liberia.
Mr Cameron has been asked by the UN to look into how poverty in developing countries should be tackled after the year 2015.
Thursday's meeting, the first of a series, will be attended by 26 members.
The panel will meet again in Monrovia and Jakarta next year, before reporting to the UN Secretary-General Ban Ki Moon.
Most of the other attendees of the London gathering are ministers from foreign governments or heads of economic committees.
The president of Indonesia, Susilo Bambang Yudhoyono, is currently on a three-day state visit to Britain, staying at Buckingham Palace. The other co-chair is Ellen Johnson Sirleaf of Liberia.