The CEO of Thames Water, the UK's largest water company, was fired with immediate effect after failing to improve performance.

Steve Robertson, who has been at the helm since September 2016, was released after a board meeting on Friday afternoon.

A source close to the company said the board, led by interim chairman Ian Marchant, said the company needed someone with greater "operational expertise" as the water company came under pressure to reduce leakage and pollution.

Thames Water is the UK's largest water and wastewater utility, serving 15 million customers in London and the Thames Valley.

It has become a lightning rod for criticizing an industry accused of raising prices for customers, failing to manage water leaks and pollution targets while paying lucrative rewards to high-level executives and shareholders.

The Labor Party of the Opposition has committed to renationalise the industry if it wins the next parliamentary elections.

Michael Gove, the environment minister, has also indicted the nine major water companies that paid dividends of £ 18.1bn between 2007 and 2016, despite the fact that total net income after tax for the same period was £ 18.8bn.

Mr. Robertson's decision is at a critical juncture as the Onwat water regulator is due to respond to the water companies' business plans for the next five-year period on 18 July.

He said he would remain an employee until June 30 to ensure a proper transition, the company said. Headhunter Spencer Stewart was appointed to find a successor.

During the reign of Robertson, the company had committed to close its subsidiaries in the Cayman Islands and to discontinue the distribution of external dividends to shareholders.

However, the company struggled to improve its performance, and was fined last year for allowing the equivalent of 180 liters of water from each house or 40 percent of the average daily water consumption of a four-person household every day.

In 2017, Thames Water was fined GBP 20.3 million after allowing 1.4 billion liters of raw sewage to flow into the Thames and its tributaries in Oxfordshire and Buckinghamshire. It received another fine of 2 million pounds last December. Both incidents were prior to the reign of Robertson.

Mr. Marchant said, "On behalf of the Board, I would like to thank Steve for his work as CEO and wish him well.

"We must continue to ensure that Thames Water is an organization that both customers and employees are proud of. We are sticking to our planned business plan, which aims to provide industry-leading customer service through a comprehensive investment program that we are committed to implementing. "