CANNABIS plants worth up to £500,000 have been discovered at a terraced house in Bolton.

Police made the discovery when they were called to Cestrian Street in Great Lever as part of a separate investigation into a road accident.

As they arrived at the house, it is believed one or two men of Oriental origin - possibly Vietnamese - fled.

When police officers went in, they discovered the huge cannabis farm.

There were more than 300 mature plants ready for harvesting on the ground and first floors of the house and about 300 saplings and younger plants growing elsewhere.

Police estimate that £30,000 had been spent on lights, fans and ventilation. The walls of every room were covered in reflective sheeting to help encourage the plants to grow.

The crooks had crudely rewired the house to bypass the electricity meter.

Sgt David Kehoe, of Bolton police's drugs unit said: "This was a huge discovery of plants which were ready to be cut, dried out and sold.

"Everything I have seen inside suggests that this was set up by someone who has very extensive experience of growing cannabis.

"There was a staggering amount of electrical equipment and sophisticated hydroponics gear to keep the plants healthy and growing as quickly as possible to maximise return.

"People might think that the growing of cannabis is a trivial crime, but it is funded by, and helps to fund, organised crime, including armed robbery."

It is thought the harvest from the female plants would have been turned into super-strength "skunk", which sells for up to £150 per ounce.

Police were called to Cestrian Street at 8am on Saturday morning after a resident reported his car had been damaged by another vehicle.

He told officers he suspected a neighbour of causing the damage - and pointed them towards his house.

Officers got no answer at the door and went to the back of the house where they found the gate and door unlocked.

Inside, they discovered plants throughout the building.

Makeshift beds had been set up in the front room of the house.

Scenes of crime officers spent the weekend examining the plants, cutting them from their containers and removing them.

Police went back yesterday morning to remove equipment that had been used.

It is believed one man, and possibly a second, had been living there to tend to the plants round the clock.

Sgt Kehoe said "We would be keen to speak to anybody with information about the whereabouts of people who were living in the house or have visited."

Shocked neighbours said they had no idea what was going on in the house.

One said: "A man moved in about three or four months ago and since then I think I've only seen him about twice, but his car was always parked in the street.

"Nobody suspected a thing until the police turned up and began taking things out of the house."

The cannabis farm is the third to be discovered in Bolton in the last three months.

About 400 plants were found in two houses in Queen's Avenue, Bromley Cross, early last month.

Both houses had been fitted with hydroponic equipment similar to that at the house in Cestrian Street and young and mature plants were growing inside.

The plants were discovered when the landlord was called to the house by engineers who said they needed entry because of an electrical fault.

Two men described as Vietnamese were seen fleeing the house.

A second farm was found in the loft of a house in Hill Lane, Blackrod, in April, where about 50 plants had recently been harvested.

Skunk is a form of cannabis so powerful that experts are warning it can be 25 times stronger than the cannabis used by previous generations. It has recently been linked to mental illness, particularly schizophrenia.

Anybody with information is asked to contact police on 0161 856 5796 or Crimestoppers anonymously on 0800 555 111.