A FORMER police constable ran a “professional” cannabis factory protected by strategically placed weapons from his village home near a school.

David Allen, aged 68, was caught after police received reports of a strong smell of the illegal drug emanating from a farm just 100 metres away from a primary school at Calthwaite, near Penrith.

Detectives went to the small holding, on July 20 last year and discovered Allen — a former PC attached to the Northumbria force during the 1990s — had been involved in the “continuous commercial production of cannabis at the property”.

A search revealed a “professional grow” of 80 plants using high end equipment designed to maximise yield. The plants were nearing full maturity, and contained within a fully insulated room complete with sophisticated timed lamps, heaters and a working industrial ventilation system. Next to that was a substantial drying area including a large, insulated tent, drying racks and vacuum-packing machinery, along with empty fertiliser containers.

Seven crops could have been produced during a 140-week period, it was estimated, potentially yielding 42kg of cannabis with a possible wholesale value of up to £336,000.

Prosecutor Alaric Walmsley told Carlisle Crown Court yesterday (TUES): “A search of the defendant’s farmhouse revealed further equipment and packaging for the cannabis; notes and manuals of how to grow cannabis and operate the machinery; cash; and weapons — knives, a crossbow and air rifles in strategic positions ready to protect the cannabis farm.”

One detective described the operation as “one of the most carefully constructed and sophisticated set-ups he had ever seen”.

After being released while under investigation by police, Allen was said to have made “arrangements to leave the country”, telling an estate agent in November he was “packing” and “off to retire in the sunshine”, mentioning “Asia” and suggesting he would not be coming back.

“In addition, a financial investigation of the defendant’s personal and business accounts identified unexplained cash deposits totalling over £425,000, together with regular transfers of money to a woman in the Philippines,” added Mr Walmsley. Two passports handed over by Allen to police featured different dates of birth.

He was arrested, remanded in custody and admitted both cannabis production and possession of criminal cash.

After hearing a prosecution opening of the case, the judge, Miss Recorder Kate Bex QC, adjourned the case for Allen’s barrister to fully prepare his submissions overnight. The hearing is due to resume and conclude later today.