A CARETAKER of historic tunnels near Kidderminster has been jailed for allowing them to be used as a large scale and sophisticated cannabis factory.

Wayne Robinson was said to have been living in fear of reprisals from the criminals involved in the operation at Drakelow Tunnels, Worcester Crown Court heard.

The 48-year-old was found guilty by a jury of allowing the factory to be set up in an abandoned part of the tunnels and also pleaded guilty to having a shotgun and ammunition without the correct certificates.

Tim Sapwell, prosecuting, told a sentencing hearing the factory was uncovered in a police raid on November 13, 2013.

It involved a sophisticated hydroponic set up and other expensive equipment with hundreds of mature plants capable of producing a crop worth up to £71,000.

There was further evidence of an earlier harvest and some smaller plants indicating that it was intended to be a large scale commercial operation.

Electricity to power the factory had been abstracted from a business called Forest Logs operated by Robinson, Mr Sapwell said.

Robinson, who had been the caretaker of the tunnels since the 1990s, was paid £200 a month rent but there was no suggestion he was involved in any other part of the operation or received a cut, the court heard.

Mr Sapwell said Robinson had been mixing with "nasty people" because of the drugs operation.

Following his arrest, his dog was poisoned, bars were painted on the portable building he used for work, a man was arrested with a taser near the premises and a gunshot had been heard at the site.

When police searched his house, they found a shotgun under a bed and machine gun ammunition in the loft though there was no evidence he had tried to conceal it, Mr Sapwell said.

Abigail Nixon, defending, said Robinson, of Marlpool Lane, Kidderminster, was a respected businessman who had been "gullible" for allowing the operation to be in place for an estimated six months.

The factory was in an abandoned part of the tunnels, which stretch for some miles, away from the parts used by the public for activities such as ghost hunting.

"He shut his eyes to what was going on," she said. "He had no idea of the enterprise apart from the movement backwards and forwards of the men setting it up."

She said he and his partner had "lived in fear" of knocks at the door for the last three years.

"The police confirm that the people they suspect of being involved would carry out their threats," Miss Nixon said.

She said Robinson had a number of other guns properly licensed and had been taking steps to get the appropriate certificate for the shotgun, which had been given to him by a local farmer.

The NATO machine gun ammunition did not fit any of the guns he owned and he was keeping it because he had found it on site and he intended to include it as an exhibit in a wartime museum planned for the tunnels.

Judge Abbas Mithani, QC, said the cannabis factory had been a "carefully planned and professional operation" set up with a great deal of skill and experience to produce a substantial amount.

Drugs factories attracted "the worst type of criminal activity" which had resulted in the threats to Robinson when it became clear he might not want to co-operate, the judge said. Only a "swift and stiff" sentence was appropriate to deter others from becoming involved.

He gave Robinson a sentence of 14 months for the drugs offence with nine months for the shotgun and six months for the ammunition offences to run concurrently.