“This investment is essential to maintain the highest-quality drinking water for a growing population, ensure the security of our water supply in the future and significantly reduce the amount of sewage entering rivers and seas,” said Water UK, which represents the sector.

The House of Lords Industry and Regulators Committee recently warned that continued underinvestment would have serious consequences for the environment and the security of water supplies.

It also found that Ofwat needed to go further to hold water companies to account for environmental pollution as well as ensure that companies invest sufficiently in infrastructure.

Water UK said that under its proposed £96bn investment regime, for the 2025-30 funding period, the number of households receiving support with bills would more than double to 3.2 million. But campaigners for clean water said billpayers should not be paying for infrastructure investment companies should already have carried...