Britain said it would provide immediate debt relief for 19 of the world's poorest countries in a move that will cost $50 million this year.

Finance Minister Gordon Brown's pledge came after the Group of Seven rich nations agreed at the weekend that they are willing to provide up to 100 per cent debt relief owed by impoverished countries to the international institutions.

"The 100 per cent debt summit this year has started with one major breakthrough: a victory in the fight to make today's poverty history," Mr Brown wrote in a letter to the organisers of the Make Poverty History campaign, released by the Treasury.

Currently, about 80 per cent of the debt faced by the poorest countries is owed to organisations like the International Monetary Fund and World Bank.

While proposals on how to write off IMF debt will be brought forward in April, Mr Brown wants the richest donor countries to take over a proportionate share of the debt and has taken the lead on this by agreeing to underwrite 10 per cent of the total.

On his recent visit to Africa, Mr Brown signed agreements with Tanzania and Mozambique to take over 10 per cent of their debt to the World Bank and African Development Bank, and said that the same offer was potentially available to the world's 70 poorest countries provided they met the conditions for relief. Similar agreements have now been reached with 17 more poor countries: Benin, Burkina Faso, Ethiopia, Ghana, Mali, Madagascar, Mauritania, Niger, Senegal, Uganda, Bolivia, Guyana, Nicaragua, Armenia, Mongolia, Vietnam and Sri Lanka.