More than 100 charities, trade unions and campaign groups have joined forces to urge Tony Blair to fight poverty.
Oxfam is predicting 45m children will die needlessly by 2015
The Make Poverty History campaign says it wants Britain to make laws stopping big business from "profiting at the expense of people and the environment".
The prime minister has declared his aim is to put development at the top of the international agenda.
But the campaign says unfair trade policies, debt and lack of aid are costing lives.
The groups supporting the campaign say Britain has done little to stop unfair and undemocratic policies being imposed on poor countries.
"We know what the problems are but until now there has not been the political will to do something about them," said Steve Tibbett from ActionAid on behalf of Make Poverty History.
"We want 2005 to be remembered as the year that changed the world," he added.
The campaign says it wants an end to exports being "dumped" in ways that harm poor rural communities around the world.
And it is also calling for the "unpayable debts" of the poorest countries to be cancelled in full and for at least an extra £50bn dollars to be given in aid each year.
'Make or break'
It argues that without such steps global poverty will not become history.
Earlier this month, Gordon Brown said next year would be "make or break" for development in poorer countries as he set out UK goals for its EU and G8 presidencies.
The chancellor outlined a series of key targets the government will be judged on in 2005, during a speech in London.
They will include doubling aid from donor countries and eliminating debt owed by the poorest nations.
Mr Brown wants other G8 nations to match his target for overseas aid - spending 0.7% of national income.
Oxfam's Paying the Price report published at the start of December said 45 million children will die needlessly before 2015 and aid budgets are half their 1960 levels.