People who want to show their commitment to tackling climate change can get a limited edition of Fairtrade, organic 'Cut the Carbon' shoelace, provided by Christian Aid.

The shoelace has been produced to support the charities' Cut the Carbon march, the longest ever protest walk which runs until 2 October.

Actors Leonardo di Caprio and Katie Leung, from the latest Harry Potter film, have backed the initiative and MOBO-award winning singer, Lemar, has already bought a pair of laces.

Christian Aid is launching a petition calling for the UK Government to commit to reducing greenhouse gas emissions by at least 80 per cent by 2050 to prevent millions of people in the developing world from suffering.

People across the UK will be invited to sign the petition card and send one of their own shoelaces to Christian Aid to show their support for the campaign. The charity is hoping to collect 1,000 miles of old shoelaces which will be presented to Number 10 with the written petition.

The limited edition 'Cut the Carbon' shoelaces are the first to hold a Fairtrade Mark. They were made by Fair Deal out of organic cotton from Egypt, but were manufactured in the UK.

The Cut the Carbon March started last week and will run until 2 October, covering 1000 miles in 80 days, and over 70 towns and cities. Part of the 'I Count' coalition, Christian Aid expects over 50,000 people to walk some part of the route joining the main 20 marchers who will travel the whole route. Rallies will be taking place in Edinburgh, Newcastle, Leeds, Birmingham, Cardiff and London.

Paul Brannen, head of campaigns at Christian Aid, said: "Climate change is the most serious threat to humanity. Poor people in the least developed countries are already dying as a result of floods, droughts and conflict over scarce resources, such as water, that are becoming scarcer as the planet heats up.

"They need our help to tackle climate change by reducing emissions, through individual actions and by putting pressure on the UK Government to pursue climate-friendly national and international policies."