Osborne and Gates pledge cash to beat malaria
Chancellor George Osborne and philanthropist Bill Gates have announced £3bn in funding over the next five years to tackle malaria.
Britain will give £500m a year from its overseas aid budget. And The Gates Foundation will give $200m (£140m) this year, with other donations of at least £110m to follow in the next five years.
The aim is to eradicate the disease.
The number of people dying from malaria is falling, but a child still dies from the disease every minute in Africa.
There were 438,000 malaria deaths in 2015, most of them of children aged under five, according to the World Health Organization.
Drugs can treat malaria, and bed nets, insecticides and repellents can help stop mosquitoes, which transmit malaria, biting.
But a quarter of children in sub-Saharan Africa still live in a household with no insecticide-treated mosquito nets and no indoor spraying with safe, long-lasting insecticides.
The malaria parasite has also begun to develop resistance to currently available insecticides and drugs.
Analysis: Tulip Mazumdar, BBC Global Health Correspondent
"We want to end malaria in our lifetimes". It's a bold ambition from chancellor George Osborne and philanthropist and billionaire Bill Gates. There have been great successes in the fight against one of the world's biggest killers, with the number of deaths more than halving since 2000.
But some of the key tools the world has to fight the disease are becoming less effective, which is why research and development of new drugs is so important. The British government says the cash could help "nearly eliminate" malaria in the next 15 years. But wiping out malaria completely is likely to take much longer, and cost far more.
Scientists are hopeful they will find new treatments and preventive methods that could eliminate malaria by 2040.
Speaking at the Liverpool School of Tropical Medicine, where scientists have identified new active ingredients that could form the basis of new insecticides, Mr Osborne said: "Tackling malaria at source, working with people like Bill Gates using Great Britain's science to do it helps Britain's national security as well as being the right thing to do to save lives in our world and that's exactly the combination that I would want to see our aid budget being used to deliver."