the crop has an estimated street value of more than a million pounds. officers say the plants were being grown in twenty large rooms with almost every part of the bunker dedicated to what they described as the wholesale production of cannabis. six men have been arrested. jon kay reports. hidden in the wiltshire countryside, rghq chilmark, a huge underground bunker built to protect britain s leaders in a nuclear war. if we go in here, mind your head. this afternoon, police showed us the vast cannabis growing operation they uncovered here overnight. how would you describe what you have discovered here? a huge, massively professional setup, the biggest cannabis factory farm i have seen in 25 years of service. to find this in the heart of rural wiltshire is quite incredible. police found 20 large rooms filled with plants and equipped with specially installed equipment. every room has got this set up in it, the venting at the top to withdraw the fumes, take that outside, contain