England's privatised water companies pledged Thursday to make massive investments to stop raw sewage being pumped into waterways as concerns mount about water quality and laxer environmental protections post-Brexit.

But campaigners expressed outrage that the billions of pounds promised to upgrade infrastructure would be passed on to consumers already struggling with higher bills for utilities.

Water firms have been under fire for years over releasing untreated wastewater into rivers and seas, blighting fragile ecosystems and leading to illnesses in people and the closure of beaches.

The long-running scandal has endured despite many of England's nine water and sewerage companies paying out billions of pounds in shareholder dividends in recent years and rewarding executives with multi-million pound remuneration packages.

Last year, three French Euro MPs even asked the European Commission to try to stop the UK releasing raw sewage as it was polluting beaches, marine life and waters across the Channel and North Sea.

They accused the UK of abandoning its international environmental regulations.

Apologising Thursday for "not acting quickly enough on sewage spills", trade body Water UK said the firms will invest £10 billion ($12.4 billion) in "the biggest modernisation of sewers since the Victorian era" in the 19th century.

The plan to overhaul 350,000 miles (563,000 kilometres) of sewers will also include the launch next year of a new environmental hub, giving the public "near real-time information" on sewage overflows for the first time.

The companies will also support up to 100 communities to create new protected waters for swimming and recreation.

Water UK chair Ruth Kelly said the plan was to introduce improvements "as fast as is physically possible".

But in a series of broadcast interviews, Kelly admitted consumers will face "modest upward pressure" on bills to help pay for the package.

- 'Oops. Sorry' -

Feargal Sharkey, the former frontman of Northern Irish punk band "The Undertones" who has become a figurehead of the campaign to improve water quality, led the sceptical response.

"This is nothing to celebrate whatsoever. What they should be saying is 'we messed this up, we're terribly sorry, we're going to compensate you all'," he told BBC radio.

"We should have an apology for the suggestion they are going to put bills up by £10 billion for their incompetence and their greed."

Greenpeace UK's policy director Doug Parr echoed the public fury around the issue.

"After years of relentlessly flooding our streams and beaches with raw sewage, an 'oops, sorry' from the water firms won't cut it," he said.

"The promised £10 billion is a start but if it's all charged on peoples' bills whilst the shareholder dividends remain untouched, that would be a very strange way of being sorry."

Last month the UK government announced its latest plan to better protect England's water supplies, promising more investment from water companies, alongside stronger regulation and tougher fines for polluters.

It included a consultation on a ban on wet wipes containing plastic, which are blamed for causing sewer blockages when flushed down the toilet, and £1.6 billion ($2.0 billion) of infrastructure investment between now and 2025.

But critics called the proposals too little too late and still leaving the water industry, in private hands, profiting from failure.

Prime Minister Rishi Sunak's spokesman said the firms' investment plans will need regulatory approval to "ensure they deliver on the targets that we've set, whilst not disproportionately affecting customer bills".

"We've been clear that we think water companies must put consumers above profits," he added.