By Richard Black
Environment Correspondent, BBC News website, New York
Six countries have pledged almost US$150m (£80m) to a proposed new United Nations emergency fund.
The fund should speed aid to places that need it
The fund would allow the UN to respond to natural disasters and other emergencies within a matter of days rather than weeks it can take now.
The British government has promised almost half of the total sum.
The pledges came during the World Summit in New York, and the proposed fund will be debated by the United Nations later in the year.
"When a crisis comes, it is to the United Nations that we look," the UK's International Development Secretary Hilary Benn told reporters.
"The UN presses the fire alarm; but in order to get the engine out of the station, it has to pass round the hat to put petrol in the tank and water in the hoses."
The proposed new fund, known as the Central Emergency Response Fund, would replace a current arrangement under which the UN can give loans for emergency operations with one which disburses grants.
The total envisaged is US$500m (£280m) per year, 10 times the sum available now.
At the World Summit, six countries pledged a total of US$145m to the fund's first year; Britain's share is US$70m (£40m), and Sweden's US$40m (£20m).
The other partners are Norway, the Netherlands, Switzerland and Luxembourg.
Swift and certain
Jan Egeland, the UN's Under Secretary General for Humanitarian Affairs, welcomed the move.
"Our responses are very uneven," he said, "and it often takes time for us to get money to teams in Niger, to anti-locust teams, to Darfur before mortality goes up.
"Now we will be able to say 'let's go' in three to four days rather than three to four weeks."
Mr Egeland also said it would enable the UN to deal with crises which are currently beyond its capabilities.
The six countries anticipate further pledges of support before the end of the World Summit, possibly from African nations.
The proposal, which relates to a clause in the World Summit draft outcome document to improve "the timeliness and predictability of humanitarian funding", will go to the UN General Assembly for approval in November.