The company has also come under intense pressure over leaks and pollution levels.

Last week, Thames Water was handed a £3.3m fine for a “reckless” incident in which millions of litres of undiluted sewage were pumped into rivers near Gatwick Airport in 2017.

Bosses said that as of March the company had £4.4bn of cash in the bank and committed funding.

Since privatisation in the late 1980s, the water industry has built up more than £60bn in borrowings and paid out more than £70bn in dividends.

Thames, which supplies 15 million households in London and the South East, was bought in 2006 by a consortium led by private equity giant Macquarie, which was subsequently criticised for overseeing growth in debts at the company while £2.7bn were paid out in dividends. Macquarie has since sold its stake.

Interim-chief executives Cathryn Ross and Alastair Cochran said: “This announcement is a major milestone for Thames and all our stakeholders.  

“The substantial equity support package announced today will underpin the delivery of a more focused turnaround plan that builds on the foundations that have been put in place over the last two years and focuses expenditure on a smaller number of initiatives, which will deliver material and sustainable improvements in key performance metrics over the next three years.”

Thames Water’s owners include Ontario Municipal Employees Retirement System, the UK’s Universities Superannuation Scheme and China Investment Corp.