A landlord has been praised after alerting police that the house in Oxford he was renting out was being used as a cannabis factory.

The landlord of the house in Harcourt Terrace, Headington, visited his property at 8pm on Thursday to discover more than 200 mature and young cannabis plants being cultivated.

Southern Electric engineers called at the house earlier today and made sure it was safe before officers seized the plants. No arrests have been made so far.

Sgt Graham Pink, of Oxford Police, said: "This landlord had concerns something wasn't right, and went in person to visit the house, uncovered this set up and called us about it.

"He did exactly the right thing and we urge other landlords to make certain their properties aren't being used for criminal operations.

"This is an issue that Thames Valley Police is taking very seriously, but we are reliant on public support to stop these factories becoming established and operating in the Oxford area.

"Vet tenants very carefully, check all references, and make sure growers aren't using your properties. They can cause tens of thousands of pounds worth of damage and it will be uninhabitable for many weeks, if not months."

It was the 17th factory discovered in the city since January 1, and it is estimated that so far this year the value of plants seized has been about £1.74m.

If left undisturbed to be harvested over a year, the drug would have fetched a total of £7m. Police have not revealed the street value of the latest seizure.

Anyone who wants to tip off the authorities can call Crimestoppers on 0800 555111.