Police believe an organised criminal gang is behind hi-tech cannabis factories found in Oxford.

The news comes after nearly 400 cannabis plants, with a potential street value of tens of thousands of pounds, were discovered in police raids on two Oxford properties yesterday morning.

The swoops are being linked to drugs raids carried out in recent weeks at properties in East Oxford - in Warwick Street and Fairacres Close in April, and Aston Street in May.

On each occasion, police found a professional hydroponics set-up and small Buddhist shrines. The houses had been converted to incorporate metallic ventilation pipes and all had only very basic home comforts.

Police spokesman Tim Wiseman said: "The professional manner of the set-up would indicate that these properties are being set up and run by organised criminals, as opposed to small domestic growing set-ups also found recently, for instance in Barton and Blackbird Leys."

Mr Wiseman said the similarities were being investigated and police forces across the country were pooling results.

He added: "There are indications that this could be linked to a wider national organised cannabis cultivation ring."

The dawn raids in Rose Hill, involving two teams of eight police officers, happened simultaneously at 6.30am at Lenthall Road and Rivermead Road.

A 21-year-old man was found inside the Rivermead Road house and arrested, while a 19-year-old man was later arrested outside the Lenthall Road house, after he pulled up in a red Vauxhall Astra half an hour after police entered the property.

The 21-year-old had to be taken to hospital, after he cut his foot on broken glass knocked on to the floor during the raid.

Police said the operations followed tipoffs from the community and after PC Martin Brock and PCSO Jacqui Harris walked past the house on Lenthall Road and sniffed the pungent cannabis odour.

Inspector Phil Standish, neighbourhood inspector for Rose Hill, added: "We are pleased with the result. This is a sizeable quantity of controlled drugs and this is very much in keeping with the information we received from the Rose Hill community in a neighbourhood meeting on Friday."

Katharine Miles, 33, who lives next door to the raided property in Rivermead Road, said: "He (the occupant) told me he had moved down from London and that the house was owned by a friend and I have never seen anyone going in and out.

"I never suspected anything like this was going on."