Police are investigating after hundreds of cannabis plants, thought to have a street value of hundreds of thousands of pounds, were discovered at a house in Bradford.

A fully-fledged cannabis factory was found at the semi-detached property in Holly Bank Gardens, Horton Bank, after police were alerted by electricity bosses.

Between 500 and 700 cannabis plants were discovered in four rooms of the house. There was also a hydroponics set-up, including heating, lighting and ventilation, along with other drugs- related paraphernalia.

Police are trying to trace the occupants of the house, but no arrests have been made at this stage. Scenes of Crime Officers attended after police were contacted by the electricity suppliers, who had attended the property yesterday.

Residents in the street said the house had been empty for a number of months. One resident, who did not want to be identified, said vans had been arriving at the house late at night and in the early hours of the morning.

The resident said: “It’s been empty for a few months. We had an inclination, but it’s hard to prove. We had just an idea that something wasn’t right. I’m pleased it’s been sorted out.”

Another resident, who did not want to be identified, said: “I’m not surprised because you hear a lot of it, empty houses being used as cannabis factories.”

The value of the cannabis has not yet been calculated, but a recent seizure of 700 fully developed cannabis plants had a street value of £240,000.

A West Yorkshire Police spokesman said: “This is a significant seizure of cannabis which was likely intended for the streets of Bradford.

“The support of local residents remains a key part in our efforts to remove drugs from our city and there are many ways to spot whether a property is being used as a cannabis factory.

"For instance, unusual activity of people coming and going, delivering fertiliser and equipment, the lights left on continually and curtains drawn and strong, pungent smells coming from the property are just some of the tell tale signs.”