No one from either was available for comment last night.

For the last full financial year to March 31, United Utilities reported an 11% rise in pre-tax profits to £530m.

That was achieved despite revenues only increasing 3%, to £2.43bn, which masked a fall in water usage by business customers.

In September, the company’s chief executive, Philip Green, was upbeat about the group’s prospects. He said it was trading “in line with our expectations of a sound underlying financial performance”.

Also in September, United Utilities submitted its response to watchdog Ofwat’s proposed levels for price increases between 2010-2015 ahead of the final determination set for this month.

Last month, the company was fined £29,000 after allowing raw sewage into Liverpool Bay.

Between January 8 and 9 last year, 13,000 cubic metres of effluent was pumped from North Wirral waste water treatment works over 12 hours.

Wirral magistrates court heard how alarms went off in the treatment plant, but the company failed to respond.

It also failed to notify the Environment Agency of the accident until 12 days later.