Welsh Water told it risks prosecution in a damning new report

Welsh Water said: “We are disappointed with the assessment rating and acknowledge that our performance is not where we want it to be.

“We take environmental responsibility seriously and apologise for any environmental harm we have caused and are working tirelessly to deliver the improvements required in challenging circumstances.”

It added climate change and severe weather events had “an increasing impact on our infrastructure and is challenging how we deliver our services”.

The NRW report also focused on the other water company operating in Wales, Hafren Dyfrdwy.

Part of the Severn Trent group, it provides wastewater services to some mid and northern border counties here.

Due to its small operating area Hafren Dyfrdwy did not receive a star rating and its performance was said to have has improved from the previous year, despite some non-compliance issues and one low-level sewerage incident.

A consultation with water companies and other relevant stakeholders will be held over the summer.