"I turned the lights on and it's 'Oh my God, 3ft of soil in my bedroom'," Charles Reeves says, still in disbelief, as he shows the BBC his home. "I'm surprised the floors are even withstanding all this stuff."

Mr Reeves, a north London homeowner, returned from working abroad to find his family home transformed into a cannabis farm.

The criminals, posing as tenants, had dumped 10 tonnes of soil in the property, causing extensive damage and leaving the family devastated.

According to experts, rental scams linked to cannabis farms are on the rise, with criminals seemingly exploiting the lengthy eviction process to complete illegal grow operations before disappearing.

The Reeves family had advertised their property online as they prepared to work abroad. They were approached by an estate agent who discovered they would be away for an extended period. The agent promised them a family of tenants, supposedly working for a City firm and with children.

However, the "tenants" turned out to be scammers who never paid rent and instead used the property for criminal activities. It was later discovered that the estate agent was operating a fake site, and the tenants were bogus.

The police told Mr Reeves it was one of the worst cases of this kind of crime they had seen. They seized more than 400 cannabis plants from the property, with an estimated street value of hundreds of thousands of pounds.

Mr Reeves went to the property after the tenants had failed to pay their rent, having gained a court order to enter the house.

He knocked on the door and was greeted by several men, with one claiming the property was in good condition. Within half an hour, these men had disappeared, although we don’t know what role they played in the farm.

"I couldn't believe what I was seeing," Mr Reeves said, describing the moment he entered the house. "The cannabis crooks dumped 10 tonnes of soil in the family bedroom.

"The whole place had been transformed into a drug factory. There were holes in the ceiling, wires everywhere, and the stench was overwhelming."

Mr Reeves discovered an elaborate setup with fans, lights and a ventilation system powered by stolen electricity. The criminals had rewired the property's electrical system to bypass the meter, allowing them to power their extensive growing operation without detection.

In addition to the tonnes of soil dumped on the upper floor, the property had suffered significant structural damage. Holes had been cut into the ceiling and walls to accommodate the complex ventilation system, which was designed to regulate temperature and humidity for optimal plant growth.

The sophisticated lighting setup, which included specialist grow lamps, had been rigged up throughout the house. The intense heat generated by these lamps also caused damage to the property, with burn marks and melted fixtures visible in several rooms.

"There was a big curtain here. This is astonishing," Mr Reeves says. "They had fans going, the lights were going, this curtain was being pulled in."

The emotional toll on the family, from both the rental fraud and the damage caused to their home, has been immense.

Mr Reeves's wife Julia said: "When you're dealing with property, particularly a home that you're in for nearly 20 years, and raising your child in... It was pretty horrific to feel that you got attacked at the core, that inner sanctum, that place of comfort, that we'd rely on in the city, it's our home - very emotional."

Mr Reeves said: "Emotionally, it feels like my home has been defiled. That's what it feels like. The damage, the dirt, all this dirt everywhere.

"This is the first real home I ever had. We're crushed and devastated."

Metropolitan Police figures show more than 1,000 cannabis farms have been discovered in London in the past few years, with a total of 1,056 found between the 2018-19 and 2022-23 financial years. However, experts believe these figures represent only a tiny proportion of the cannabis farms currently in operation.

According to Allen Morgan, one of the UK's leading expert witnesses from criminal drugs trials and a former police officer who now runs a drug consultancy service, rental fraud linked to cannabis farms is increasing.

"We're seeing a definite uptick in these types of crimes, with criminals taking advantage of the rental market to set up illegal grow operations," he says.

"The criminals exploit the legal system and the eviction process. They know that it can take months to evict a tenant, even if they stop paying rent. During this time, they can complete multiple grows and make a significant profit before disappearing without a trace."

The lack of regulation in the rental property sector has made it easier for fraudsters to operate. Estate agents are not required to have qualifications, despite handling significant assets. This can leave homeowners vulnerable to scams and other criminal activities.

"If something sounds too good to be true, it probably is," Mr Morgan warns. "If somebody turns up offering to pay cash because they've been let down and they need to move in immediately, then alarm bells should start to ring."

The cannabis trade has evolved from small-scale grows to sophisticated multimillion-pound operations, allegedly run by international crime syndicates. London, with its vast local market and extensive transport network, has become a hub for drug distribution.

"The issue that London has is obviously it is one of the main distribution hubs for controlled drugs throughout the United Kingdom," Mr Morgan explains.

"The cannabis trade is so lucrative, what you get is when you convert a rented property, you effectively obtain five, six, maybe seven separate growing areas where you can produce cannabis plants, obviously discreetly and without any sort of evidential link to you."

Police have stated that what happened to the Reeves family is still under investigation, but the reality is that innocent landlords are being left to pick up the pieces of London's growing drug crime problem.

The Reeveses hope that by sharing their story, they can raise awareness of this growing problem and prevent other homeowners from falling victim to similar scams.

"We want people to be aware of the risks and to take every precaution when renting out their properties," Mr Reeves said. "No-one should have to go through what we've experienced.

"Not only was it the fraud, it was a destruction of our home."