A property firm has been fined £1,500 for polluting the Mill Brook, a tributary of the River Thames, in Wallingford.

Portarlington (UK) Ltd, of West Lodge, Streatley, allowed mineral oil to seep into the brook from a pumping station on the Beadle industrial estate.

The commercial property leasing company, which was responsible for the estate's drainage system, was aware of the oil but took no action, Didcot magistrates were told.

The Environment Agency received reports about the oil, but was unable to locate its source.

Janet Fedrick, prosecuting, said the agency removed the pollutant from the brook, but continued to receive complaints.

On December 17, the company admitted causing oil to enter the brook, which feeds via the Bradfords Brook into the River Thames.

In addition to the fine, it was ordered to pay £4,166 costs to the Environment Agency.

The agency's enforcement team leader, Rod Gould, said: "Water coming out of our taps originates in rivers fed by tributaries such as these."