The Word health Organization (WHO) has asked donor countries for $14 billion to fund its next five-year strategic plan which it said will 30 million lives by 2023.

For the first time the pitch for the new funding has been presented as an "investment case" with accountants calculating the money will add 2-4 percent economic growth to low and middle income countries over the period.

By improving health outcomes, the report argues, donor countries will be making a major investment in the 'human capital' of developing nations. That, in turn, will benefit donor countries as trade grows.

As well as improved GPD, the money - equivalent in total to about a 12th of the annual budget of the NHS - will add an estimated 100 million years of healthy living to the world’s population.

Jane Ellison, assistant director general of the WHO, told The Telegraph that she was "optimistic" about reaching the $14.1 billion goal.

"I am optimistic about raising the money. We're essentially saying that we want to be accountable and transparent. That should give donors old and new the confidence to invest - it's the right time to set out our ambitions."

The organisation's budget includes a $10 billion base budget, representing a 14 per cent increase on current levels. They have also set out plans to spend $2.5 billion on humanitarian and emergencies and $1.6 towards polio eradication.