Storms and heavy rain have caused sewage to be discharged into the river running through Bath and Bristol, making it unsafe for swimming, according to environmental campaign group Surfers Against Sewage.
The SAS group has issued two alerts for the River Avon in the region, covering the popular wild swimming spot at Warleigh Weir near Bath, and the Floating Harbour in the centre of Bristol.
The city council in Bristol has long banned swimming in the docks, saying it is unsafe, but that is being challenged by a Bristol-based campaign group of wild swimmers, set up by Johnny Palmer, the businessman who owns Warleigh Weir.