THEY followed their noses - and sniffed out the biggest cannabis factory ever found on Oxford's Blackbird Leys estate.

PC Alex Shepherd and PC Phil Gardiner, of the Blackbird Leys pro-active team, were carrying out routine patrols last Saturday morning when they grew suspicious about a house in Balfour Road.

They knocked at the door and, when there was no answer, forced entry and found 250 fully mature cannabis plants in three rooms in the house and in the loft.

PC Shepherd, 22, who is based at Cowley, said: "We were on routine investigations for an unrelated matter when we smelt the cannabis. We recognised a few other signs from past experiences of finding these things and realised this could be a cannabis factory.

"There were 427 plants in the house and this is the biggest find we have had in Blackbird Leys to date, and possibly in Oxford.

PC Shepherd said they were pleased with the discovery, particularly since Blackbird Leys residents have highlighted drugs as one of their biggest concerns on the estate.

He said: "Finding this is very significant for the community of Blackbird Leys. They have highlighted that drugs are a problem and we know we need to combat this.

"There have been about ten discoveries of cannabis factories so far this year."

Last month, firefighters stumbled across a £30,000 cannabis factory in Headington. More than 500 cannabis plants were seized with a street value of £30,000.

No one has been arrested in connection with the discovery at the weekend.