By Alastair Leithead
BBC News, Afghanistan
Flying over the river valleys of Helmand, southern Afghanistan, the lush green crops leap out of the monotonous beige desert landscape, spreading out as far as the eye can see.
Helmand's stability is intertwined with that of its opium trade
In the well-tended plots the farmers harvest their crop, but much of it is neither wheat nor vegetables - it's a cash crop and it's worth a huge amount of money.
Field after field is full of opium poppies and the gum the labourers are extracting is the raw material for heroin.
Helmand province in southern Afghanistan is where hundreds of British troops are already stationed and where hundreds more are currently being deployed.
This year Helmand will produce half of Afghanistan's opium, and the profit it will make for the traffickers and dealers as it moves its way to the UK will top one billion dollars.
The British government's commitment to Afghanistan is not just military support and reconstruction - but a pledge to taking on the drugs problem.
And when you realise that around 90% of Britain's heroin originates in Afghanistan you can see why it's an attractive political goal.
The extent of Helmand's poppy farms can clearly be seen from the air
But on the ground it's a complex and dangerous job for the 3,300 British troops who will be on the front line against roadside bombs and suicide attackers intent on maintaining instability.
Half Afghanistan's economy is drugs dependent, and the Taleban, Al Qaeda and local warlords all make a lot of money out of narcotics - it fuels the insurgency here.
As one British military official said, the drugs problem is stamped across every level of the peace-keeping, or peace-making mission here.
It's a big business that has made allies of former enemies.
The mission is to bring stability to allow development and reconstruction, and to help extend the hand of the democratic government to areas currently out of its control.
Drugs and the problems they bring with them stand in the way of that mission.
Persuading people to stop growing poppies needs a combination of increasing the risk and the consequences to them of getting caught, and at the same time helping to provide them with alternative ways of making a living.
Poppy eradication is carried out by the government, but it is dangerous, labour intensive work, and what is cleared is a fraction of the total crop.
Helmand's anti-opium campaign is seen as integral to its future
Mahmoud Naiam has been growing vegetables for two years now - he used to be a poppy farmer, but is now part of a USAID project which is providing training, seed and plastic greenhouses.
The aubergines and cucumbers are good and the technology gets them to market earlier and later in the season to earn the best prices, but whether this business is sustainable in the long term is the question.
"We only know how to grow poppies well," says Mahmoud. "If the aid workers give us seed and help it's fine - but if they leave, we'll go back to farming poppies."
In a police cell in central Kabul sit 31 tonnes of seized drugs - half the weight marijuana, but the rest opium, brown heroin, or the chemicals to purify the resin into a consumable drug.
Again it's a fraction of what is produced, because Afghanistan's borders with Pakistan and Iran are long and the smuggling routes are numerous and well-trodden.
From the dusty trails that meander the desert crossings, opium and heroin are trafficked out to Europe and into the veins of Britain's heroin junkies.