An Oxfordshire MP has attacked Thames Water in a speech in parliament.

David Johnston, Conservative MP for Wantage and Didcot, was speaking in a debate about the strategic priorities of water regulator Ofwat.

He said: "In 2021, Thames Water released sewage into the waterways around Oxford for more than 68,000 hours. What Thames Water did is completely unacceptable and totally against what it should be doing according to its licence. This should be a rare occurrence with very heavy rainfall, but it is anything but that."

He said huge numbers of houses have been built in his constituency with the biggest town "growing by 42 per cent in 10 years, and the second by 59 per cent - but the infrastructure has not improved."

"We also have the issue of the water and waste connections that go to these new developments, some of which are huge. These are big-scale developments, and, too often, what happens is that these systems are not built strongly enough in the first place, and they are easily overwhelmed.

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"Those costs are then very often passed on by management companies to the people who have bought those homes, which is a subject for a separate debate. Again, this should not be happening, and we must get a lot better at tackling it."

He then talked about the proposed Abingdon Reservoir, which would cover nearly seven square kilometres of farmland between Steventon, East Hanney and Drayton, saying "Thames Water is still unable to show why it is needed, why it is better than the alternatives, what the environmental impact will be, and what the cost is likely to be."

"We know, thanks to GARD—the Group Against Reservoir Development, the dedicated local campaign group—that some of the assumptions that Thames Water used when it tried to make the case about water demand and so on are wrong. We know from Thames Water’s own website that 24 per cent of the water that it supplies leaks, which leads to many of my constituents saying, 'Well, actually, perhaps we wouldn’t need this reservoir if you fixed your leakage problem.'"

He said Ofwat should be holding Thames Water to account and getting it to answer the big questions about the proposal and "make sure that Thames Water cannot behave, as many people feel that it is behaving, as though this is an inevitability".