Leonie Dubois, Head of Engagement, Land and Consents at Thames Water, said: “The South East is designated as seriously water stressed and as we enter the fourth heatwave of the summer it’s clear climate change is already having an impact.

“It’s therefore critical that we continue to progress our plans for White Horse Reservoir.

“It would act as drought insurance policy for the region, securing water supplies for 15 million people, including Thames Water, Affinity Water and Southern Water customers.”

The White Horse Reservoir, near Abingdon, will provide water for 15 million people across the south east.

The project has been labelled a “vital piece of national water infrastructure” by Thames Water.

But, in a statement action group ‘Group Against Reservoir Development’ called the reservoir the wrong solution in the wrong place.

The massive reservoir, which will cover an area the size of Gatwick Airport, has always been a topic of debate.

Only Kielder Water in Northumberland, at 200 billion litres, is bigger.

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Map of Abingdon reservoir location. (Image: Google Maps)

Two groups, Countryside charity CPRE Oxfordshire and Safer Waters, even sought a judicial review at the High Court.

However, their judicial review was dismissed.

 Thames Water revealed that costs for the controversial proposed Abingdon Reservoir soared from £2.2 billion to between £5.5 billion and £7.5 billion, a tripling of the original figure

This will be borne by customers of Thames Water, Affinity Water, and Southern Water.

The plan is to tackle an anticipated shortfall of more than a billion litres of water per day in the next 50 years, according to Thames Water.

This projection considers the effects of population growth and climate change.

Thames Water predicts that a severe drought could cost London’s economy alone as much as £500m a day.

Currently, hosepipe bans are already a common occurrence.

The Abingdon Reservoir, also known as the South East Strategic Reservoir Option (SESRO), is expected to be the second largest reservoir in the UK, with a capacity of 150 billion litres.

Only Kielder Water in Northumberland, at 200 billion litres, is bigger.

The site is located three miles southwest of Abingdon.

It is close to the River Thames and features the right geology and ground conditions for a reservoir.

Thames Water has had to plan for more than just the reservoir itself.

The project will include a pumping station, a conveyance tunnel to transfer flows to and from the River Thames near Culham, and infrastructure to link the reservoir to the River Thames for emergency drawdown.

An access road into the site, a temporary rail siding for freight train deliveries, and a compensatory floodplain are also part of the plan.

Local streams will be diverted, and the Steventon–Hanney road will be shifted to the south.

Cambridge Tech Week has named five startups as finalists in its 2026 pitching competition after judges selected them from a shortlist of 20 companies.

The finalists are HotHouse Therapeutics, HutanBio, Lambda Energy, Myonerv and Xplore Intelligence. They span biotechnology, sustainable energy, agritech, medtech and artificial intelligence, reflecting the breadth of the wider shortlist.

HotHouse Therapeutics emerged from Professor Anne Osbourn’s laboratory at the John Innes Centre. The company is developing a drug discovery approach based on transient plant expression, using living plants to produce new medicines through an artificial intelligence-led platform.

HutanBio is focused on algae-based fuel production. It has identified a new class of algae, called Sphaerica, that produces oil at much higher rates than existing leading strains and can be cultivated in seawater on non-agricultural coastal land using sunlight and CO2.

Lambda Energy operates in agritech with a greenhouse additive called GloGro. The product is designed to increase crop yields by about 20%, and the company has secured pilot manufacturing and grower trials for high-value crops in the UK.

Myonerv has developed a wearable neurostimulator designed to monitor and treat stroke-induced paralysis remotely. Its system uses reusable electrode arrays and has already demonstrated remote control of hand movement between Cambridge and Greece.

Edinburgh-based Xplore Intelligence is building software to train and evaluate AI agents. Its Forge platform is designed to simulate operational environments so businesses can test full AI agent systems before deployment. The company has also won its first contract, worth more than GBP £1 million.

Judging panels

An independent panel drawn from finance, venture capital and industry reviewed the initial shortlist. It included Paul Hughes, Managing Director – Life Sciences & Technology, BDO; Jamie Bignal, Director, HSBC Innovation Banking; Mayank Shah, Co-founder and Chief Executive Officer, Grow Beyond Borders; Anne Dobree, Investment Director, Parkwalk Advisors; Isabelle O’Keeffe, Venture Partner, Twin Path Ventures; and the Chief Technology Officer for His Majesty’s Government Communications Centre, whose identity was withheld for security reasons.

A separate panel will choose the overall winner in the live final. It includes Zickie Lim, Partner and Head of VC & Investments, Mills & Reeve; Marilena Ioannidou, Director, Metaxi Catalyst Ventures; Richard Lewis, Managing Director, Foresight Group; and Emmi Nicholl, Chief Executive Officer, Cambridge Angels.

The competition forms part of Startup to Scaleup Day, one of the business-focused strands of Cambridge Tech Week. Organisers have positioned it as a showcase for younger technology businesses seeking investor, customer and market attention as they move beyond the early stage.

The finalists also highlight where UK startup activity remains concentrated. Drug development, climate and energy technologies, digital health, food production and AI infrastructure continue to attract commercial and investor interest, particularly when linked to research institutions or clear industrial use cases.

Cambridge has long been one of the UK’s leading centres for venture-backed science and technology businesses, with strong links between academia, investors and corporate partners. The inclusion of companies from outside the city, including Xplore Intelligence, suggests the competition is intended to reflect a broader national technology base rather than the local cluster alone.

The pitching competition is sponsored by Mills & Reeve, PwC and Julius & Clark. Professional services and law firms have become regular backers of startup competitions as they seek closer ties with high-growth businesses and their investors.

Lead judge Zickie Lim commented on the selection process.

“The standard of this year’s competition has been exceptionally high from the start, which will make the final selection process incredibly challenging. As sponsors of the Pitching Competition, Mills & Reeve is delighted to support a platform that shines a spotlight on the next generation of innovative businesses, and we are looking forward very much to seeing the finalists pitch live at Cambridge Tech Week,” Lim said.

PwC also highlighted the strength of the field.

“This year’s finalists demonstrate the extraordinary depth of innovation emerging from the UK’s technology ecosystem, and are among the strongest we’ve seen. They all represent the kind of ambitious, globally relevant businesses that have the potential to create real impact. PwC is proud to support entrepreneurs at this critical stage of their growth journey,” de Young said.

Chris Weston, speaking on the BBC’s Big Boss Interview podcast, stated that some of the firm’s targets were beyond what they could achieve.

He said: “We have to hit a certain level of leakage, but it is so far in excess of what we are capable of doing, I think anyone would be capable of doing, however much money you invested, that it is not going to be achievable.”

Thames Water, the largest water company in the UK, has been under fire recently for its handling of sewage discharges and leaks.

Last year, it was fined a record £122.7 million by regulator Ofwat, largely for breaching sewage spill rules.

The company, serving 16 million customers in London and parts of southern England, treats 4.3 billion litres of waste daily.

Mr Weston mentioned that “99.5% of the time” the waste is treated successfully, although “sometimes something goes wrong”.

He added that while the company wants to improve on pollution, the chance of getting to zero pollution was “very, very slim”.

Ofwat responded to Mr Weston’s comments by stating: “With around a fifth of water put into supply still lost through leakage, companies must deliver on the commitments they have been funded to achieve.

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(Image: PA)

“Water company targets are intended to be ambitious and drive better outcomes for customers and the environment.”

The Environment Agency spokesperson said the agency and the public expect Thames Water to comply with the law, adding that the agency would continue to hold companies to account where performance falls short.

James Wallace, chief executive of campaign group River Action, criticised Thames Water.

He said: “Thames Water’s tactics of opacity and deflection fool no-one.

“Telling the public to save water while this wasteful profit-obsessed corporation leaks 570 million litres of treated drinking water every day is offensive.

“There is nothing ‘realistic’ about accepting sewage pollution as inevitable.”

Thames Water has been grappling with billions of pounds in debt and faces the risk of temporary nationalisation, known as a special administration regime.

Mr Weston, however, warned of the potential burden on taxpayers if this were to happen.

Instead, he backed a rescue deal proposed by the firm’s lenders.

Meanwhile, Mr Weston defended the company’s pay levels, as his pay rose by 14% to £1.163 million in the year to March, while other directors received bonuses totalling £4.1 million.