Ofwat said it has concluded its investigation into Northumbrian Water — securing an enforcement package of £15.7 million to be paid by the wastewater company and its shareholders, not customers.

Ofwat is the body responsible for economic regulation of the privatised water and sewerage industry in England and Wales.

“This package is greater than the penalty which would otherwise have been imposed on the company,” said Ofwat.

“It ensures this money will remain in the water sector and be spent on making improvements to services for the benefit of Northumbrian Water customers and the local environment.

“If a penalty had been applied, the money would have been returned to the Consolidated Fund operated by HM Treasury.”

Lynn Parker, Senior Director for Enforcement at Ofwat, said: “Our investigation has found failures in how Northumbrian Water has operated and maintained some of its sewage works and networks, which has resulted in excessive spills from storm overflows.

“The contraventions we have found at some of their sites will have had an impact on the local environment and customers and it is unacceptable.

“We are pleased that Northumbrian Water has agreed this package. We now expect them to move at pace to correct the issues our investigation has identified.

“We hope more companies will follow this example so that the public sees transformative change across the sector.”