The world's eight major industrialised nations agreed to a "significant" amount of extra money to fight the Afghan drugs trade on Thursday after Britain admitted efforts to curb it had not succeeded. British Home Secretary Charles Clarke said more cash was essential if the West was to stop the flow of drugs from Afghanistan which accounts for 87 percent of world's illicit heroin trade, according to Reuters. The United States, Britain and other countries have already committed millions of dollars to the cause since the ousting of the Taliban but have so far seen little return. The United Nations has warned that Afghanistan risked becoming a "narco-state" unless action was taken. "We know that there are major problems, that we haven't succeeded in doing what we needed to do," Clarke told reporters at a meeting of interior and justice ministers from the Group of Eight nations. He said the G8 summit had agreed to inject a "significant amount" of new money into the issue, although he declined to reveal the exact total, and would seek closer cooperation with other states in the region. In addition, it was agreed that they should work more closely with the government in Kabul to ensure the money went towards the desired objective of getting investment into the Afghan countryside to switch opium production to other crops. "There needs to be a lot of work done ensuring the money goes where it needs to go," Clarke said, adding Britain would keep the top responsibility for dealing with the issue.