POLICE looking into allegations of human trafficking in Blackburn "discovered a cannabis farm" during their investigation.

Officers said they were originally contacted by Greater Manchester Police regarding an allegation of human trafficking in Blackburn.

A 32-year-old woman had reported the alleged offence to officers in Greater Manchester. But when officers attended an address in New Wellington Street, Mill Hill, yesterday, they discovered 30 cannabis plants, police said.

A 28-year-old man has been arrested on suspicion of producing a class-B drug and was last night in custody. Police said they were no longer investigating allegations of human trafficking.

It comes as almost £500,000 of cannabis was seized in a series of raids across Blackburn and Haslingden on Tuesday.

Neighbours in New Wellington Street said they were suspicious something was going on at the house after catching whiffs of the class-B drug.

One resident said: “The police were carrying plants and equipment out of the house.

“We heard them banging the door down at 3.30am and the neighbour’s dog was barking. It woke everybody up. We had some indication that this was happening — we could smell it all the time.”

Another resident said: “The police had two black boxes, tubes of metal piping and bags of plants. It is a shock that this is happening on the street.”

During Tuesday’s raids around 1,220 cannabis plants were seized.

Officers said each plant was valued at around £400.

Several rooms in each property, four homes in Blackburn and one in Haslingden, were being used to cultivate plants, with sophisticated hydroponic systems used to water them, officers said.

Four people were arrested and three have been charged in connection with the raids.

A police spokesman said: “We were contacted following an allegation of human trafficking in Blackburn. Police were called after a 32-year-old woman reported the alleged offence to officers at Greater Manchester Police. Following inquiries, officers later attended an address in New Wellington Street.

“A 28-year-old male from Blackburn was arrested on suspicion of producing a class-B drug and is currently in custody. Inquiries are ongoing.”