Yehia Hassan is on the verge of tears as he surveys the filth and broken furniture strewn across the front room of his beloved Luton home.

It’s a scene the 78-year-old’s family feared him seeing because of the impact it might have on his health.

“It was perfect in here,” Hassan, who has diabetes and uses a wheelchair, says. “I just don’t know how people can do this to someone else’s property. It’s the only place I have.”

His terraced house was gutted by renters and converted into a cannabis factory while he was receiving hospital treatment in Egypt.

Police raids at his property and a neighbouring address uncovered hundreds of cannabis plants, but the occupants have not been found.

Figures obtained by the BBC show thousands of cannabis farms have been discovered by police across England in the past three years.

In Bedfordshire alone, police have seized plants from residential properties with a street value of about £6m over the same period.

A retired foster parent, Hassan says he rented his home to a local business owner and allowed him to sublet it to others.

“I really trusted the guy,” Hassan says. “He said he was going to look after the place. But honestly, I don’t know who I can trust any more.

“All my life I have worked for this house. It’s going to cost tens of thousands of pounds to put everything right.”

The constant demand for properties has led drug farmers to look beyond private landlords like Hassan.

Bedfordshire Police say there is a growing issue of “professional enablers subletting to criminal networks for the cultivation of cannabis”.

“We are now seeing estate agents involved in many of the factories we enforce against,” says Det Insp Simon Mullan.

“Estate agents are unregulated, which is one of the big problems, and criminals are exploiting this industry for their own ends” he added.

Hassan is currently living with his ex-wife and relies on the support of his 19-year-old daughter, Razan.

“I was due to go to university, but have put that on hold to sort this out,” she says.

“There is still no power because the renters rewired everything and were stealing electricity from the entire street.”

Not a single part of her childhood home was left untouched by the drugs operation.

In the space of just a few weeks, criminals bored large holes in the walls for extractor fans, hung heavy lights from the ceilings and removed a fence panel, apparently to enable access from a third property.

The back garden now resembles a landfill site, with a huge pile of seed trays, lumber, compost and empty bottles of growing solution left behind.

Ornate cabinets designed by Razan’s mother have been torn apart and dumped in the bathtub and the bedrooms are still littered with the remains of harvested plants.

“The house reeked when we first got here, it was genuinely atrocious for months,” Razan says.

She says they learned about the police raids through a Facebook post, which showed their home had been “decimated”.

“It came as such a shock because the person who was renting it from us had called two weeks earlier saying everything was fine,” she says.

“His attempts to redecorate have been lazy at best. Holes were barely filled, the paint job was limited and messy, and there were still pots of cannabis culture in the master bedroom.”

The BBC contacted the businessman who rented the property, who says he had sublet it to a builder.

“He paid the rent on time and, I’m not going to lie, I wasn’t checking on the property. I’m not an estate agent.

“At the end of the day, these things happen and I’m a few thousand pounds out of pocket myself,” he says.

The BBC has chosen not to name him.

Responding to Hassan’s case, Bedfordshire Police told the BBC that while “no suspects had been identified”, they were “working with the family to establish new lines of inquiry”.

“We have a dedicated team to tackle this element of organised crime and recently secured our first conviction of an individual who illegally sublet a property for the cultivation of cannabis.”

Hassan’s neighbour, Abdul Shakoor, says the criminals kept a low profile, and nobody knew they were there.

“I was woken up by a loud noise when the police came and saw one of the suspects running away,” he says.

“There are so many of these farms; in two years I have seen three of them on this road. The police just come and take away the plants.”

It is thought 90% of cannabis in circulation in the UK is produced in farms set up in rented homes, external.

Deputy Chief Constable Paul Court, of the National Police Chiefs Council, says cannabis production is “linked to serious violence and exploitation”.

He says while the “majority of landlords are law abiding citizens” there had been “several cases recently where they have been prosecuted for their involvement” in cannabis cultivation.

Recent cases of rental properties being taken over have seen cannabis crooks knock down walls in a couple’s detached house in Norfolk and dump ten tons of soil in the upstairs bedroom of a family home in north London.

Court says: “We recognise the impact this crime can have on the rental sector and ask landlords to be vigilant and keep regular contact with tenants.”