So they claim leaks fell - and so they did for a while. Meandering around the horizontal from about 2000 onwards. No continuing improvement.I can't see that. There is a good article explaining the situation with water companies in the news today.
Knee-jerk nationalisers have no idea how the water industry actually works - CapX
Basically, OFWAT sets the target of water loss and pollution for water companies. The more money they invest or waste, the more they get paid. So if it's only up to the water companies, bills will go up very fast. If government wants to freeze prices, then they will have to accept degradation of the pipes.
If Starmer wants to re-nationalise, he'll have to borrow upward of £100 billions and prepare to invest many more billions every year fixing leaks.
Gas is a different thing. I can see government building gas storage facilities, buy the gas and sell it to marketing companies to retail to the public. It's still not a case for re-nationalising though.
My personal involvement in a water leak, around 2014, showed me how poorly Thames were operating. My estimate of losses is around 20,000 litres a day. Which might have been going on for months - or years.
Noticed by us - not Thames. Hindsight led us to believe that end of the garden had retained moisture because of the leak rather than rain and good soil!