Former American President Jimmy Carter paid a flying visit to Oxford today in his second visit to the city within a year.

Mr Carter was guest of honour at this year's Skoll World Forum on Social Entrepreneurship, hosted by Oxford University's Said Business School.

The conference aims to unite social entrepreneurs, academics and economists, to address solutions to global health issues, environmental sustainability and poverty.

Shortly after noon, Mr Carter, 83, called in at the Randolph Hotel, in Beaumont Street, shaking hands with a well-wisher, before moving on to the Sheldonian Theatre, off Broad Street, for an awards ceremony, where he made a brief speech.

Stephen Chambers, chairman of the Skoll Centre for Social Enterpreneurship, said: "We are delighted former US President Jimmy Carter is attending the Skoll World Forum, where he will present the Skoll Awards for Social Entrepreneurship.

"These celebrate the huge achievements social entrepreneurs from around the world, working in an untold number of fields, have made to foster tangible social change."

Last July, boatman Jack Allen got the surprise of his life when one of his punt customers was Mr Carter.

The 19-year-old took the Nobel Peace Prize winner and three companions for a brief trip on the River Cherwell near Magdalen Bridge.

Mr Carter was staying in the city for a few days after receiving an honorary degree from Oxford University.

The theme at this year's forum is Social Entrepreneurship: Culture, Context and Social Change.

Al Gore, 2007 Nobel Laureate and former Vice President of the US, is speaking at the conference today.

Topics at this year's forum include: The role social entrepreneurs play in post-conflict states to speed up economic and political stability The unique contributions women are making to the field of social entrepreneurship and the cultural barriers they have faced.

In 2006, Robert Redford and Mr Gore attended the Skoll Foundation Forum at the Said Business School.

Last year, US civil rights leader Jesse Jackson visited students at Regent's Park College in Oxford to promote more applications to Oxford University from black students.

Mr Carter was the 39th President of the United States from 1977 to 1981, and was awarded the Nobel Peace Prize in 2002.

Before becoming President, Mr Carter served in the Georgia Senate.