The dimly lit basement reeks of hashish. Piled high along a wall are dozens of large white sacks filled with the leaves and seeds of the Cannabis sativa plant. In one corner lies a sprawling 8ft-high haystack of dried marijuana plants awaiting threshing and sieving into powder and compressing into blocks of hashish.

With his armed bodyguards looking on, Abu Rida grasps a thick fluffy bunch of dried leaves and sniffs them appreciatively. “I believe that the hashish grown here is a blessed and holy plant,” he said.

Abu Rida has good reason to thank his blessings. The biggest cannabis farmer in Lebanon, he has just taken in the largest harvest of the lucrative crop since the late 1980s, when the sun-baked plains of the northern Bekaa Valley were awash with cannabis and opium poppies.

Usually, Lebanese police backed by soldiers and armoured vehicles destroy the cannabis crops just before harvesting in late summer. This year the overstretched Lebanese Army was unable to support the police raids because of security commitments elsewhere in the crisis-plagued country, including a three-month battle against Islamist militants in the north.

Also, the farmers were determined to protect their crops. Local tractor owners normally hired by the drug police to plough up the fields were warned by the farmers to stay away this year or their houses would be burnt down. When the police began tearing out cannabis plants by hand, the farmers shot at them from nearby buildings and woods with machine-guns and rocket-propelled grenades.

One of those firing the rocket-propelled grenades was Abu Rida.

At 36, he has built a multi-million-dollar fortune from hashish. Sentenced to death in absentia by the Lebanese State for past drug-related murders, he lives in a fortified compound protected by gun-toting militiamen drawn from his home village.

The northern Bekaa is a lawless district where the Government carries little weight against the powerful tribal clans. In its dusty villages stolen cars and weapons are traded, opium resin from Turkey and Afghanistan is refined into heroin and coca paste from South America is turned into cocaine.

The pony-tailed Abu Rida, more than 6ft (1.8m) tall and powerfully built, keeps a 9mm automatic pistol in a shoulder holster slung beneath his jacket. “I run this village. Everybody works for me. We are a big clan and they all belong to me,” he said.

He agreed to talk freely but asked that his real name and the village where he lived should not be printed.

The fertile Bekaa Valley has a long history of growing the cannabis plant. It was not until the lawless years of the 1980s, midway through the 16-year Lebanese civil war, that cultivation soared, turning peasant farmers into multimillionaire drug lords and generating an annual economy of $500 million in one of the most impoverished areas of Lebanon.

The biggest dealer in the Bekaa was Jamil Hamieh, a farmer from Taraya village, who built a fortune from cannabis and heroin. At his height in the late 1980s, he hosted Colombian drug barons and Italian Mafia dons eager to buy his drugs. He is the only Lebanese cited on the US Government’s list of international drug kingpins.

Now retired, Hamieh lives in an air-conditioned tent, Bedouin style, erected beside the mansion he built for his family. “It wasn’t the Government that made me stop. I was tired of being ripped off by all the foreigners I was dealing with,” he said.

With the end of the war in 1990, the Lebanese Government, with the help of the United Nations Development Programme, ushered in a drug eradication programme to encourage farmers to grow alternative crops. The scheme met with success initially and by 1994 the Bekaa was declared drug-free. But the promised international funds to finance the programme did not materialise. By 2001 only $17 million of the pledged $300 million had arrived and the programme fizzled out a year later. Since then the disgruntled farmers have begun returning to cannabis cultivation in ever-growing numbers.

The northern Bekaa Valley is dominated by the militant Shia Hezbollah party of Lebanon. Officially, Hezbollah disapproves of drug production but it has chosen to turn a blind eye to the practice rather than confront the clans that dominate the area.

Abu Rida owes his continued freedom and survival to cash payouts to police, politicians, army officers and even clerics. He can afford to be generous. He cultivated more than 568 acres of cannabis this year. That was processed into 20 tonnes of resin – worth about $13 million (£6 million).

‘Assassin sect’

— The term “hashish” refers to the resin derived from the cannabis plant. It is widely linked to the Hashashim sect of Ismaili Shia Muslims active from the 11th to 13th century, from which the word “assassin” is thought to originate

— The sect was founded in 1090 by Hasan-i Sabbah to disable the Abbasid Caliphate, with a campaign of murders targeting its most notable members

— According to popular tales, sect members, or hashishiyun, would consume hashish to promote fearlessness before their missions

— Hashish is also said to have been used as a tool for drugging new sect recruits in an effort to establish loyalty. Some argue that this is merely fiction, popularised in Western Europe by the Crusaders