The company had invested, on average, about £1bn a year for the last 15 years in strengthening its infrastructure and customer service, one source said. The nationalisation of Britain's water companies has been a long-standing pledge from the current Labour leadership team spearheaded by Jeremy Corbyn and John McDonnell. Thames Water was taken over by Macquarie, the Australian infrastructure investor, in 2006, in an £8bn deal. Anglian Water and Yorkshire Water's parent company are still said to be weighing potential challenges to be lodged with competition authorities. City editor It is expected to feature in the party's election manifesto when it is published next week. Mr Robertson's departure in May came after a period of poor operating performance, with Thames Water under growing pressure to curb the vast amounts of water leaking from its network. "We have a committed and strong leadership team driving our plans forward, and our focus on delivering for customers and protecting the environment remains unchanged while the search continues.". In a statement on Friday, a Thames Water spokesman said: "The board of Thames Water has been conducting a thorough search for a CEO. Thames Water appoints Sarah Bentley as chief executive officer, starting this autumn. I am delighted to be joining Thames Water, a business that clearly plays an essential role in London and the Thames Valley and which has such a strong sense of public value. In a further sign of the renewed scrutiny that the industry is facing, its main lobbying group, WaterUK, this week announced that it was replacing its own boss. Thames is easily the UK's largest water and wastewater services company with an annual turnover of £2bn. The water and waste group, which has a total of 15m customers, has been searching for a new chief since May, when it ousted Steve Robertson after less than three years in the job. Estimates vary about the likely cost of carrying out that threat against an industry which has been beset by a poor record on water leakage and repeated scandals relating to the treatment of sewage. ", Thames Water powers ahead in search for new chief. This is a critical time for the company, and alongside her passion for customers, Sarah is clearly the perfect person to lead our multi-billion pound investment programme and develop our longer term strategy to ensure a resilient water and waste service for generations to come.”. Sarah Bentley to be new chief executive of Thames Water . The company has brought in specialist restructuring advisers amid concerns that Ofwat's ruling could make it impossible to service its £12bn debt mountain. In 2017, Thames Water was fined more than £20m for dumping raw sewage into the River Thames and its tributaries, with a second, smaller, penalty imposed the following year. A number of the major operators are preparing to take the regulator to the Competition and Markets Authority if they are hit by what they perceive to be unfair rulings. If Mr Scarsella had joined Thames, his appointment would have been welcomed by shareholders given his experience in the utilities sector. Thames Water was taken over by Macquarie, the Australian infrastructure investor, in 2006, in an £8bn deal. More than 6,000 people work for the company. (Reuters) - Thames Water, one of the largest UK water companies, said here on Friday its Chief Executive Officer Steve Robertson had stepped down by mutual agreement.. Among her achievements, Sarah led the transformation of Severn Trent’s digital customer experience, as well as delivering a fundamental shift in the company’s leakage performance – leading to significant improvements in customer satisfaction. There is little doubt, however, that the party's pledge to nationalise industries widely perceived to be delivering poor customer service has struck a chord with some voters. Industry analysts believe Thames is unlikely to appeal, having received a final settlement that was less draconian than feared. Britain's biggest water company is lining up a top executive from the energy sector to be its new boss ahead of a general election that could trigger the company's nationalisation. The news that Thames is resuming its search for a chief executive comes six weeks after it was told by the industry regulator to cut customers' average bills by more than 7% over the next five years.