One of the points made quite astutely in the FT comments section mentioned that ofwat was also strongly responsible for this.
Apparently the regulatory model is set up in the following way - in order to encourage investment in infrastructure, the calculated amount that customers are charged is based on a ratio of how much money is invested into infrastructure. Supposedly Thames Water and other water companies in England wanted to invest more in infrastructure, however ofwat did not allow it as they wanted to protect customers from price increases. Furthermore because of the silly shell game of holding companies that were set up to move the debt around, ofwat didn’t understand just how much debt was being racked up and didn’t make any moves to stop it.
However what this all shows is that the regulatory model is absolutely broken. So not only is ofwat toothless in allowing a ridiculous corporate structure to be set up to obfuscate the silly financial leveraging going on, they are also operating on an entirely faulty premise.
What it all shows is that trying to set up a functional privatised system for water companies that incentivises investment and works for citizens is extremely difficult, is prone to regulatory capture, is still under pressure from meddling ministers and ultimately costs more for customers and the government than servicing the government debt that would be used to pay for investment under a nationalised system.