The area used for cultivating opium around Britain's main base in Afghanistan nearly quadrupled in three years, Foreign Office Minister Hugh Robertson has revealed.
Mr Robertson said poppy fields in the Nad' Ali district near Camp Bastion in Helmand province took up 19,136 hectares of land in 2013, compared to just 5,413 in 2011.
While the UK does not collect its own figures, it contributes funding to the UN Office for Drugs and Crime which produced the statistics.
Mr Robertson, who published the findings in response to written parliamentary questions from Labour's Paul Flynn (Newport West), said Nad' Ali was the closest district to Camp Bastion for which figures are available.
The analysis also showed the area used for opium production more than doubled in just one year, as 8,038 hectares were used for poppy cultivation in 2012.
Mr Robertson said reducing opium production would take "a generation of effort and Afghan will".
He admitted the international community misjudged its ability to cut down poppy cultivation and the heroin trade in the early years of the war in Afghanistan.
Helmand, where UK forces are based, is Afghanistan's largest opium producer with 100,693 hecatres of land taken up by poppy fields, compared with 63,307 in 2010.
Mr Robertson said: " In the early years of the intervention it is clear the international community underestimated the complexity of the problem and the length of time needed to address the drugs trade and build up the capabilities of the Afghan government after three decades of civil war.
"Achieving a permanent reduction in opium cultivation will take decades - it needs a strong Afghan lead supported by effective regional and international action.
"Despite falls in cultivation between 2007 and 2010, the narcotics trade in Helmand remains strong and entrenched in the political, social and economic fabric of the province.
"Ongoing challenges of poverty, insecurity and effective rule of law continue to create the conditions where some communities are dependent on opium cultivation to survive.
"Helmand is particularly susceptible to this problem due to its relatively porous border with Pakistan which is exploited by smugglers, and its history of opium production. This however should not detract from the progress made in security, political participation, improvements in education and health care that have been achieved in Helmand with the support of the UK.
"Significantly reducing opium production in Helmand will require a generation of effort and Afghan will. The UK will continue to support efforts to provide a viable alternative to poppy cultivation in Helmand.
"We will do so through the Comprehensive Agriculture and Rural Development Facility (CARD-F), which promotes legal rural employment and income opportunities by increasing the profitability of local agriculture and small business."