Water industry sources said companies faced pressure from Ofwat to close old facilities to save money, as well as scrutiny from the regulator over the financial benefit of opening new ones. 

Water companies say they face widespread opposition in building new reservoir facilities, despite a recognition they will be increasingly needed under drier conditions as a result of climate change. 

Thames Water has spent more than a decade attempting to construct a £1 billion reservoir to serve more than eight million people in Abingdon, Oxfordshire. The plans were first rejected by the government in 2011 and have been the subject of local opposition. 

There are plans for a handful of new reservoirs across the country, but only one - the £100 million Havant Thicket project, near Portsmouth - actually has planning permission.  

“We need to make the bureaucratic hoops easier,” said Mr Hughes. 

A spokesman for Water UK, the industry body, said reservoirs were “just one of the sources used to supply water to customers”.

The spokesman added: “New reservoirs are subject to lengthy scrutiny from regulators about their near-term need and value for money, as well as planning permission. 

“One new reservoir - Havant Thicket – is due to be completed by the end of this decade, and companies have made a further 18 proposals which are under consideration in a new streamlined arrangement introduced by regulators to speed-up and facilitate their decision-making and make it more likely that projects can proceed.”

Companies ‘put short-term profits ahead of long-term water supply’

By Andrew Sells, chairman of Natural England from 2014 to 2019

Fifty years ago, my father had a small business in East Anglia which built lakes, including those at Balmoral and the RSPB headquarters in Bedfordshire. 

In the subsequent half a century, many farmers across the country have learned the lessons of droughts in winter as well as summer, and built reservoirs on their land. 

At the same time, several of our water companies preferred to build houses on some of their reservoirs (Thames Water refuses to say how many) and last week we learnt that together they have built precisely zero new reservoirs in the last 30 years, despite population growth of about 10 million. 

No doubt some reservoirs had reached the end of their working lives - but in abandoning this critical infrastructure, without any replacements, they have again put short-term profits ahead of long-term water supply. 

Long before this news came, the water companies were in the politicians’ sights. In January, the environmental audit committee found that a “chemical cocktail” of sewage, agricultural waste, plastic and persistent chemicals was polluting our rivers and concluded that “the public are rightly shocked when they discover that untreated or partially treated sewage is dumped into rivers”.