A pollution spill in Afon y Bala, North Wales, has led to a warning that people should not swim in the river. The source of the spill has been identified by officials as leaked heating oil.

Natural Resources Wales (NRW) officers are continuing to monitor water quality at Llyn Padarn, near Llanberis, following the incident on 12 June in Afon y Bala, the river which feeds into the lake.

A spokesman said the source was heating oil from a tank at a nearby premises which leaked into the foul sewer and entered the sewage treatment works.

He said: “After discovering the pollution, Dwr Cymru acted immediately to contain as much of the oil as possible within the sewage network to prevent further pollution entering the river.

"The discharge has now stopped, but officers will continue to monitor the situation in the affected areas until water quality returns back to normal.  People may continue to notice some discolouration of the water over the weekend."