Cooped up in a tiny box room of a semi-detached home in east Brighton an Asian man sleeps, eats and washes. Every other room in the house is packed with pungent cannabis plants and drug-cultivating equipment.

The bathroom resembles an industrial mixing plant, filled with chemical fertilisers used to stimulate the drug's growth.

There are racks of bright UV lights suspended from the ceilings, heating fans and a network of 30cm wide ventilation pipes.

Welcome to 16 Ashurst Road, Moulsecoomb, one of a string of homes rented out by criminal gangs to grow high-strength cannabis.

To anyone looking at it, it is a normal semi-detached house. But passers-by are believed to have been noticing a strong smell of cannabis coming from inside and reported it to police.

And, as The Argus speaks to neighbours, the strong smell of the drug still lingers. Walking through the front door reveals why.

It is believed that up to 600 plants at a time were grown in the property - with an estimated street value of around £200,000. They can be harvested four times a year bringing in a potential annual income of £800,000.

Officers had broken down the door to the three-bedroom house at 9.30am yesterday. Inside they found a 30-yearold man who said he was from Korea and who police believe was acting as a live-in caretaker for the operation.

He was arrested on suspicion of cultivating cannabis and taken into custody for questioning.

Officers recovered 100 plants from the lounge but Sergeant Ray Avery, who is leading the investigation, said up to 500 others had already been cropped from its bedrooms and distributed for sale.

Inside, the house hardly resembled a home and instead could only be described as a factory. While the single occupant was using one downstairs room to live in, the rest of the building was given over to the drug. Plants were grown in individual pots in illuminated rooms where the walls were covered in silver foil to help them retain heat.

To divert the smell of the potent plants out through the roof of the house, the pipes had been fed through holes cut into the ceilings of the rooms.

To power the lights, heating and ventilation fans, each of the upstairs bedrooms had seven double plug sockets, and 11 other power lines. The cables for all these electrics were crudely tacked to the walls up the stairs, across the landings and into the rooms, damaging the plaster.

In the downstairs room where plants remained, the cabling had caught fire and had to be replaced.

Blackened stripes down the walls showed where the cables had burnt out.

Engineers had to be called to make the electricity supply safe so the officers could remove the remaining plants.

In the bathroom, large bottles were laid out in front of the bath, in which the scummy residue of previous fertiliser mixes could clearly be seen. On the landing, two large bunches of bare stalks lay on the floor, suggesting a large amount of leaves and buds had already been cropped - adding to the pervading smell.

Moulsecoomb resident Keith Soutter, 52, said: "It's normally so quiet around here and it's not as bad as people say it is. You get these episodes every now and then and it gives the whole area a bad name. You get so many people moving here that are renting accommodation they come and go and it's difficult to keep track of people."

Semi-retired Dave and Val Goodall, in their 60s, were visibly shocked when The Argus told them about the raid.

Mrs Goodall said: "I saw the police van up there this morning but I didn't know what it was."

Brighton University student James Toone, 22, has lived next door to the house since September.

He said: "That stuff doesn't bother me when it's just weed.

They keep themselves to themselves, it was a quiet house."

Detective Chief Superintendent Kevin Moore said: "What there is in the South East region, and even more broadly than that, is a particular problem that we are classifying as Vietnamese organised crime.

"A number of these cannabis factories are being run by gangs of people originate from Vietnam.

"Cannabis factories are one stage of this operation and there are much higher levels of criminal activity above that. They are linked to to much more serious crimes. We have evidence that they are involved in kidnap, extortion and gun crime. While that has not had a huge impact on Sussex, we have unearthed a number of cannabis factories here. They are renting properties and then using them to grow cannabis on a large scale.

"We often end up dealing with the lowest end of that, what can best be termed as gardeners."

He added: "We have not yet had a significant arrest or investigation in this region. What intelligence and evidence is tending to suggest is that these groups originate from within the Thames Valley area and due to police operations these are being pushed down into the southern counties."

Sgt Avery warned people renting out flats, pointing out that the damage to this house was likely to cost several thousand pounds to put right.

He said: "You can have the nicest house, rent it out in good faith and then it can be trashed like this one has."

Anyone with suspicions about properties should call police on 0845 6070999 or Crimestoppers on 0800 555111.