A HUNTINGDON man charged with helping to cultivate millions of pounds worth of cannabis at a barn in Haddenham has claimed he was unaware any illegal drugs were being grown. Kevin Hart, of Elm Close, believed the barn was being used to grow a type of sage and immediately severed his ties with the operation after realising that the plants were cannabis, a court heard. Standing trial at Cambridge Crown Court, the 41-year-old pleaded not guilty to a charge of conspiracy to produce cannabis. The charge relates to the discovery of more than 7,000 skunk plants, a powerful strain of cannabis, at Tree Farm in Haddenham in July last year, the largest haul ever discovered by police in Cambridgeshire. At court yesterday (Tuesday, June 14) crown prosecutor John Farmer described the operation as highly professional and said that if all plants were left to reach maturity, their street value could have been as high as £3million. Examination of the premises showed the inside of the barn, which had a little less than six thousand square feet of space, has been converted to a highly professional standard in order to be a cannabis farm, he said. Mr Farmer told the jury the barn was originally rented by Mr Hart in 2007 after an item was placed in an agricultural publication advertising its availability. More than £200,000 of modifications were made to the barn, on Hill Row, to make it capable of housing the plants, with extractor equipment, hydroponics and high powered lighting brought in. A 220kw generator was also installed which, the prosecution said, racked up bills of more than £46,000. The jury was also told that the barn cost Mr Hart £1,750 per month in rental charges. Mr Farmer said that Mr Harts fingerprints had been discovered by police on equipment inside the barn and highlighted an invoice from a company that supplied carbon dioxide, a crucial component to plant growth, inside Mr Harts car. The prosecutor told the court that Mr Hart would claim that he was only involved with maintenance of the property and believed the equipment was for the intensive production of salvia divinorum, a variety of sage that causes hallucinatory effects. The trial continues.