Sir Paul McCartney is urging fans to join his campaign to cut down on meat consumption in an effort to slow climate change ahead of next week's United Nations summit.

In a video posted online, he called for people to get involved with his Meat Free Monday climate pledge, asking them to stick to a vegetarian diet for one day each week.

The rearing of livestock for consumption is a major contributor to the production of greenhouse gases which are thought to hasten climate change.

In the video, filmed in a garden, he says: "Listen I need your help, all I want you to do is log in on pledge.meatfreemondays.com and pledge your support to the idea of meat-free Mondays - all you need to do."

Last week his family teamed up with MP Gregory Barker, David Cameron's climate adviser to launch an an online campaign to encourage skipping meat and reducing carbon footprints.

Heads of state will gather with UN secretary-general Ban Ki-moon next week in New York to discuss climate change.