The two leaders of the Catholic Church in Britain will lead the Make Poverty History march in Edinburgh next Saturday to put pressure on world leaders who are due to meet for a G8 summit.
Cardinal Cormac Murphy-O'Connor, the head of the Catholic Church in England and Wales, and Cardinal Keith O'Brien of Scotland, will lead the mass protest rally which is expected to draw at least 100,000 people.
"There is suddenly a real chance - the sort that comes but once in a generation - for Africa to reverse its three decades of stagnation," Cardinal Murphy-O'Connor wrote in the Sunday Times newspaper.
"There is a moral awakening abroad, probably the greatest awakening since the movement to end slavery in the 18th century."
Cardinal Murphy-O'Connor said he hoped to put pressure on the heads of government to change the trade laws and agricultural subsidies which he described as "ethically grotesque."
"Africa has resources and a treasure of human gifts and energy. But without a political will on the part of the G8 countries, it cannot begin to reverse its decline."
A spokesman for the Cardinal said the two men would lead the march and later say mass.
The leaders of the Group of Eight industrial nations meet amid tight security on July 6th-8th at the Gleneagles Hotel 40 miles north west of Edinburgh.
British Prime Minister Tony Blair, who holds the chair this year of the exclusive G8 club, has put battling climate change and helping Africa beat the combined curses of poverty, debt and disease at the top of the summit's agenda.
A host of celebrities including Bob Geldof and Bono have called on the British public to support the anti-poverty campaign. They have also organised eight free concerts around the world to raise awareness, called Live 8.