POLICE should have staked out a £250,000 cannabis factory in a bid to arrest the Vietnamese gang who were operating it, according to a councillor.

The 1,500-plant drugs farm, in the disused Merrie England pub, St Hubert's Road, Great Harwood, was raided by officers early on Friday.

Concerns have been raised that officers did not make more effort to make arrests.

But police chiefs have hit back and said their actions - and the subsequent arrest of a 39-year-old man - were the right ones to take.

Deputy leader of Hyndburn Council Peter Clarke said police would struggle to catch the men.

Coun Clarke, who represents Great Harwood, said: "I would have thought that the officers would have staked the place out.

"It would have only been a few days and you would have expected that they could have caught the gang - they had to come back to the pub.

"They could have even installed sensors or devices to alert them if anyone entered the building.

"No-one in the area or any residents knew the drugs were there so they could have waited a few days before dismantling the place."

Police said they were keen to seize the drugs as soon as the discovery was made in order to safeguard the evidence.

More than 1,000 cannabis plants were found growing in the pub, which has been closed for eight months, along with more than 20 large black bin bags full of dried cannabis that had already been cultivated.

Police said the expensive electronics that were found in the venue, along with the "enormous" drugs haul, was worth hundreds of thousands of pounds.

The drugs themselves could be worth as much as £250,000.

In the pub there were five rooms dedicated to growing cannabis, one was full of around 100 small plants.

Another had almost 1,000 medium sized plants while another room had hundreds of fully mature plants.

Inspector Chris Saville said: "The main reasons for taking the action we have taken were to secure the scene as best and as quickly as we could.

"A large number of bags of already cultivated cannabis were discovered inside the premises and by taking prompt action we have prevented these drugs reaching the streets.

"There was also the issue of the mains electricity supply having been tampered with which we had to address as quickly as possible because it was an obvious severe fire risk.

"An extensive investigation is underway which will be forensically led."

A 39-year-old man has been arrested on suspicion of the production and being concerned in the cultivation of a Class C drug and has been released on police bail until February.