More than 250 cannabis plants were discovered in Great Yarmouth on Wednesday and part of a road had to be dug up after a member of the public reported 'a funny smell'.

A cannabis factory, described by police as a 'professional operation' and a 'commercial set-up', was discovered after officers walked into an unlocked house on Granville Road in Yarmouth, following a report from a member of the public at 9.50am that a gate was open and back door was off its hinges.

It was also reported that there was a funny smell coming from the address that could be cannabis. A 32-year-old woman has been arrested and bailed to return to police today (Thursday, September 27), as officers continue their investigations.

Police found the entrance to the house was unlocked and discovered a cannabis 'factory' - a growing set-up in upstairs rooms, including the attic. More than 100 mature plants and more than 150 seedlings were found inside. Lighting, insulation material, an air filtering and irrigation system, fans and foil lining the walls were also found in the rooms.

Sergeant Bob Cairns of Gorleston Safer Neighbourhood Team said: 'This is a professional operation, a commercial set up. I wouldn't imagine it to be a one-off, it is likely linked to other factories locally and nationally.

'The operation behind it is likely to be county-wide or national. The criminals usually want to put themselves in a domestic setting where they are not going to be noticed, that is what attracts them to places like this, where people will not be on the look out for it.

'This is reflective of a national problem. Commercial cannabis factories are as likely to be found in any residential street, in yours as anywhere else.'

The cannabis seized had a rough street value of �15,000, and police estimate that four crops a year from the factory could turn a profit of �100,000 for the crooks.

The drugs would not necessarily flood the streets of Gorleston, but rather be distributed across the country, as part of a network of factories and distributors.

Sgt Cairns added that something on this scale was unusual for the area, but cannabis cultivation in houses is becoming more common.

EDF Energy were called out after concerns were immediately raised about the electricity supply at the house, where the mains appeared to have been bypassed.

Part of Granville Road had to be dug up to get to the relevant wiring and isolate the power.

The reason for the back door being off its hinges is unknown, but it is clear that this is what led to the member of the public smelling the cannabis.

The downstairs of the property had been kept as a typical living space, 'if you'd stayed on the ground floor you wouldn't have known anything was up, bar the smell,' added Sgt Cairns

A Norfolk Constabulary spokesman said: 'The factory was discovered as a direct result of a call from a member of the public and officers are urging anyone who may have information about the production or supply of drugs – or who may have suspicions about individuals or addresses that may be being used to grow cannabis - to contact police.'

This comes after Yarmouth police carried out four separate drug warrants last week In Cobholm and three in Gorleston during August and early September.

Sgt Cairns said that Wednesday's find was most likely linked to the previous warrants, as it was the result of 'community intelligence'.

'People are more aware of the drugs on their doorstep,' he said.

'Last week's raids were based on community intelligence, and that breeds community involvement. People become aware it is right on their doorsteps.

'We like to thank the public for bringing this to our attention, and ask them to continue to be on the look out.

'And we will continue to crack down on these sorts of offence.'

As reported, police have been cracking down on drugs in Gorleston after swooping on three homes.

Officers from the safer neighbourhood team raided properties in Blackwall Reach, Nelson Road and Church Road and seized drugs and growing paraphernalia in the searches.

The team had gathered intelligence from the community before executing the warrants.

The first raid, on Saturday August 11, was at a home in Blackwall Reach.

A small bag of herbal cannabis was seized and a 31 year old man was issued with an �80 penalty for possession of the drug.

In the second search, at around 8am on Wednesday, September 12, the team found ten cannabis plants growing in the loft of a home in Nelson Road. They also found growing equipment, which was seized along with the plants. Officers cautioned a 49 year old woman after she admitted growing the plants.

In the most recent raid on September 14, the team searched a home in Church Road. A number of plants were found in the back garden of the property and herbal cannabis and growing paraphernalia were seized. Enquiries are ongoing into this find.

Drugs were seized and arrests made as Great Yarmouth's elite Pro-active policing unit carried out drug warrants in Cobholm on Wednesday, september 19.

Four people were arrested as police swooped in morning raids on four addresses in Cobholm.

Men aged 18, 21 and 31 and a 30-year-old woman were arrested for various drug offences after officers carried out two raids at Beavans Court, one at Mill Lane and one at High Mill Road - detaining one person at each of the addresses.

At Beavans Court, 18-year-old Liam Whittle was arrested on suspicion of possession of cannabis after a small amount of the drug was seized. He has now been charged with possession and is due to appear at Great Yarmouth Magistrates Court on the afternoon of Wednesday, October 3.

At another address in Beavans Court a 31-year-old man was arrested on suspicion of cultivation of cannabis after four plants and small bags of the drug were discovered. He has now been cautioned for producing cannabis and possession after admitting growing the plants.

At Mill Lane a 21-year-old man was arrested for possession of cannabis with intent to supply and possession of a weapon, after a CS spray cannister was found at the property, which discharges a noxious gas. He was taken into custody at Great Yarmouth Police Investigation Centre, interviewed by officers and has now been bailed to return to police on October 26.

Police seized a bag of white tablets from a house at High Mill Road, arresting a 30-year-old woman on suspicion of possession of a class A drug as well as cultivation of cannabis after four cannabis plants were also found in the back garden of the property. She was interviewed and has now been bailed to return to police on October 27, pending further enquiries.

Police have chosen not to name three of the suspects as they are not currently facing court.

Inspector Nathan Clark, who oversees policing in the Cobholm area and led the morning raids, said officers would continue to target those suspected to be involved in the production and supply of drugs.

Insp Clark said: 'We receive information about the supply of drugs from many sources, including the public, and will aim to carry out warrants where there is evidence of offences being committed.

'Officers from the Cobholm & Southtown Safer Neighbourhood Team have conducted house to house visits in the area to give residents the opportunity to raise community concerns about drugs misuse and anti-social behaviour and this work will continue.'

Anyone with information about the production or supply of drugs can call police on 101 or contact Crimestoppers anonymously on 0800 555 111.