Thames Water's assertion that it can "design out" significant risks of embankment failure associated with its proposed reservoir near Abingdon "doesn’t stack up," a district councillor has claimed.

The Southeast Strategic Reservoir Option's (SESRO) potential to cause floods was debated at Vale of White Horse District Council's October meeting on Wednesday, October 23.

SESRO is set to nearly be as big as Gatwick Airport, holding 150 billion litres of water.

It would span 6.7 square kilometres and provide water to customers in London and the Thames Valley region.

An artist's impression of South East Strategic Reservoir OptionAn artist's impression of South East Strategic Reservoir Option (Image: Thames Water) A cross-party motion, proposed by Liberal Democrat councillor Robert Clegg and seconded by Green councillor Sarah James, argued Thames Water has not yet addressed community concerns around the risks of embankment failure and flooding.

Councillor Clegg said: "Thames Water claims they can 'design out' all significant risks of embankment failure, but this just doesn’t stack up.

"With the possibility of an emergency discharge coinciding with a natural flood, the results could be catastrophic."

He called for a "thorough risk assessment and public scrutiny" before any approval is granted for SESRO.

An artist's impression of South East Strategic Reservoir OptionAn artist's impression of South East Strategic Reservoir Option (Image: Thames Water) Vale of White Horse District Council leader, councillor Bethia Thomas, expressed her commitment to ensuring the interests of residents are prioritised when facing proposals and activities controlled by external organisations, such as the reservoir.

She said: "We have very little control over the outcome of Botley West Solar Farm, and of course SESRO.

"Our residents are also being inconvenienced daily by Network Rail’s continued closure of the Botley Road.

"As national infrastructure projects, they are out of our direct control, being determined by bodies over our head, but I am making sure that each of these projects does not go unchallenged."

Olly Glover, MP for Didcot and Wantage, added: “I share the concerns being raised by constituents and councillors about the serious safety implications of the reservoir proposal.

"This is the largest bunded reservoir in the UK, and to my knowledge, the world.

"With homes, businesses (and of course people) in the path of any potential dam breach, I support the council’s request for a Flood Emergency Plan to be developed before a reservoir of this scale is permitted, let alone built.

"I will continue to raise flood and the many other risks associated with Thames Water’s proposal with the relevant ministers and repeat my request for a meeting with the Secretary of State and for meaningful engagement with residents and businesses who will be directly impacted if this scheme goes ahead.“

In a Westminster Hall debate this week Mr Glover also raised the lack of public trust in Thames Water being able to successfully project manage the construction of a reservoir of such scale.