1. Why pay? Let Thames Water collapse and take back control via primary legislation. If that scares investors off future privatisation projects then good.
You can't just take it. There are many costs involved, even under special administration. If Thames collapses, there won't be any money there to pay for it.
It'll come out of your taxes.
2. Thames Water is already demanding huge subsidies on top of a 40% hike in prices, so it’s a choice between that money being used the fix the problems or it going overseas to investors.
I don't know the full details, but there are some kind of legal requirements that mean those investors must be paid a certain level of return. This is part of the bind.
The other is a combination of regulator-imposed limits on what can be spent on repairs, maintenance and Capex.
2. It wasn’t dire performance that led to privatisation, it was ideology.
The UK had already been prosecuted by the European court because our water quality had fallen so far below standard. We were going to get hit a second time if we didn't get get everything fixed up to minimum standard, but the cost of that was massive (something like £430 billion in today's money) and the only viable funding was private investment. There was an ideology spiel that came with it, about competition, innovation, etc and some of those improvements have indeed come about. But primarily it was about finding the money to get out of the doghouse.
Most obviously would stopping shareholders dictating how a private company provides a public service of critical infrastructure.
Given how much of a **** show of incompetence and underfunding the industry was in the 60s and 70s, you'd soon have people very willing to pay for a better service.
All you'd do by renationalising is give people another reason to complain about government incompetence.
Above all services on which people depend to live should not be run for profit.
It isn't run like that.
It has, however, been asset-stripped and mortgaged by previous owners (RWE and Macquarrie), and shafted by a clueless and toothless regulator.