Image caption The report said police had tripled their effectiveness at seizing drugs

Afghan opium cultivation has reached a record level, with more than 200,000 hectares planted with the poppy for the first time, the United Nations says.

The UNODC report said the harvest was 36% up on last year, and if fully realised would outstrip global demand.

Most of the rise was in Helmand province, where British troops are preparing to withdraw.

One of the main reasons the UK sent troops to Helmand was to cut opium production.

Media playback is unsupported on your device Media caption David Loyn reports from the village where Afghans have been buried after being executed for trying to smuggle opium into Iran

The head of the UN office for Drugs and Crime (UNODC) in Kabul, Jean-Luc Lemahieu, said that production was likely to rise again next year, amid uncertainty over the withdrawal of most foreign troops and the presidential election.

He said that the illegal economy was taking over in importance from legitimate business, and that prices remained high since there was a ready availability of cash in Afghanistan because of aid.

"As long as we think that we can have short-term, fast solutions for the counter-narcotics, we are continued to be doomed to fail," he added.

Mr Lemahieu said there had been some recent successes, including the arrest of leading figures in the drugs industry, but it could take 10-15 years to deal with Afghanistan's opium crisis, even if policies improved.

The report said the total area planted with poppies rose from 154,000 to 209,000 hectares, while potential production rose by 49% to 5,500 tonnes, more than the current global demand.

Half of the cultivation area is in Helmand province.

Analysis The consequences of Afghanistan's huge opium production have had an effect across society here. There are believed to be more than a million opium and heroin addicts - one of the largest levels in the world - taking advantage of plentiful supplies. The amount of land given over to opium in 2013 was 209,000 hectares. The potential production from that is estimated to be more than annual global demand, according to the head of the UN office for Drugs and Crime in Kabul, Jean-Luc Lemahieu. After rising sharply in the years after the Taliban successfully stopped production, the harvest last peaked in 2007 and is expected to continue rising. Mr Lemahieu said that the rise since 2010 was caused principally by what he called a "hot political market" - uncertainty over the process of transition from US control. That uncertainty will continue with the end of foreign combat operations and the presidential election next year.

Meanwhile two northern provinces which had previously been declared poppy-free - Faryab and Balkh - lost that status.

The report called for an integrated, comprehensive response to the problem.

"If the drug problem is not taken more seriously by aid, development and security actors, the virus of opium will further reduce the resistance of its host, already suffering from dangerously low immune levels due to fragmentation, conflict, patronage, corruption and impunity," it said.

But the report said there were some encouraging signs, with police tripling their effectiveness to capture "well over 10%" of production and a growth in services set up to tackle addiction.

The findings of the latest report reverse a decline in production last year attributed to bad weather and disease.

However, cultivation has been rising yearly since 2010 despite government efforts to eradicate the crop.

More farmers have been trying to grow the poppy as the price of opium has been rising.

Afghanistan produces more than 90% of the world's opium.