The fungus kills opium poppies, the raw material for the drug.

The UK Foreign Office has confirmed a report in The Sunday Times newspaper that Britain is helping to fund the biological research.

The programme is based in Uzbekistan, in central Asia, which borders the so-called "Gold Crescent" of countries that supply up to 90% of Britain's heroin.

Opium poppies in Afghanistan

The action comes after bumper harvests have seen the UK and much of western Europe flooded with cheap heroin. The street price has halved and seizures at ports and airports have risen sharply.

The Foreign Office was unable to confirm details of the report, but a spokeswoman stressed that work was "in its very early stages at the moment."

Spending so far was to "find out whether the project is viable," she added.

She could not confirm the report's claim that Britain had contributed $500,000 to the programme, a figure matched by the US.

But she did say the UK's share was part of its total contribution to the United Nations' Drug Control Programme, based in Vienna.

Heroin seizures in the UK have risen

Britain would hope to unleash enough fungus to infect thousands of acres of poppies in grown in the central Asia region.

America would be expected to deploy it in the "Golden Triangle" regions of south-east Asia, and South America, where most of its heroin originates, says the newspaper report.