Christians concerned about climate justice will be among the thousands of campaigners expected to march in London on the eve of critical international climate change talks in Nairobi.

They will join the march this Saturday leading to the I Count rally in Trafalgar Square, organised by the Stop Climate Chaos coalition.

The Bishop of London, the Rt Rev and Rt Hon Richard Chartres, will preach at a special Service of Challenge, Commitment and Blessing at Grosvenor Chapel.

The service has been organised by Operation Noah - a Christian environmental movement set up by Churches Together in Britain and Ireland and Christian Ecology Link.

The congregation will hear the bishop preach on the issues of the day before he leads them to a rally in Grosvenor Square, ahead of the march to the Stop Climate Chaos gathering in Trafalgar Square.

This week saw the publication of the highly anticipated Stern Review on the Economics of Climate Change which set out the risks of climate change for the world's poorest and most vulnerable people.