We can certainly prevent 100m Aids cases, we can certainly prevent 40m orphans

"If we want them to participate in finding a vaccine we will have to give them financial incentives to do so," he said.

Mr Clinton also called on governments to learn from each other. He suggested that programmes introduced in some countries could be applied elsewhere.

He citied prevention programmes in Cambodia which have seen a 30% reduction in HIV among pregnant women in four years and a prevention and treatment programme in Uganda which has seen the overall adult HIV rate fall by almost half in four years.

"All we need to do is take what works wherever it has been implemented and implement it everywhere Aids is," Mr Clinton said.

Government funding

The former president urged western countries to contribute to the fund being set up by UN secretary general Kofi Annan to help pay for treatment programmes. Mr Clinton said the programme would cost in the region of $7bn annually.

This is not rocket science. It is a matter of money, organisation and will

But he said: "This is far cheaper than picking up the pieces of the shattered lands and shattered lives that we will live with if there are 100m Aids cases in 2005."

Mr Clinton highlighted the scale of the disease when he said: "About two and half times as many people die every day from Aids as died on September 11 from the terrorist attacks."

He suggested private companies could also play a role in fighting the disease.

"Beyond the governments of the world contributing to the secretary general's fund and continuing their effort to find vaccines, businesses can do a lot as well."

Role for business

Mr Clinton suggested companies could contribute computers and marketing expertise to improve health promotion campaigns while they could also offer Aids and HIV screening tests to employees and their local communities.

All we need to do is take what works wherever it has been implemented and implement it everywhere Aids is

He said the International Aids Trust was working "to tap the genius people have for fighting Aids at the grassroots level wherever we find it and then to spread it."

He added: "It is maddening to go into a place where you seen have Aids basically banished and ask yourself if it happened here why hasn't it been done somewhere else, why isn't being done everywhere else. Why is anybody dying if all these people are alive.

"This is not rocket science. It is a matter of money, organisation and will. Yes, it won't be over until we develop a vaccine or some other cure but we can certainly prevent 100m Aids cases, we can certainly prevent 40m orphans. The tragedy of 2005 doesn't have to become a reality."