VALE of White Horse District Council has called for a public enquiry in response to plans to build a reservoir the size of Heathrow Airport near Abingdon by 2043.

The council says it is concerned that Thames Water has not correctly followed procedures in its draft Water Resources Management Plan and has not fully explored each option in sufficient depth.

Council leader Matthew Barber said: “We are yet to be convinced that the proposed reservoir at Abingdon is necessary or indeed the most effective option to address the future water needs of the south east of England.

Pressure is building on the company, with widespread criticism coming from various bodies in recent weeks.

Campaigners in the Group Against Reservoir Development (GARD) have called for a new public consultation on the proposed artificial lake, labelling the current consultation, which closes on Sunday night, "a shambles".

GARD has vowed to continue its long-running opposition to the proposals and is drafting its own response, already stretching to hundreds of pages, which has to be submitted by midnight on Sunday.

Speaking at a meeting of the Wantage and Grove Campaign group on Thursday evening, GARD’s Chairman, Derek Stork, said: “We think that there needs to be a second consultation because this consultation has been a shambles. Thames has abandoned population figures halfway through and forced to concede to the minimum leakage target.

“You cannot get anything meaningful about cost. There are undeniable errors in what’s called the deployable output, which is basically the water available from non-reservoir sources.

"There is an improper, incomplete simulation of more extreme drought.

“When you analyse the draft proposals, it appears that Thames Water has not actually done a more sophisticated optimisation of options. There’s no doubt Thames will revise their programme. They’ve publicly had to admit to certain aspects of it being wrong anyway.”

GARD has vowed to put pressure on the Department for Environment, Food & Rural Affairs and environment secretary Michael Gove for a second consultation on Monday morning, after they have filed their response.

Mr Stork insisted Thames Water overestimated water shortages, and should focus on other ways of getting water – particularly in reducing leaks.

He said the company's figures were wrong and that the environmental impact and disruption caused by building work would be significant.

He added that the proposed 150 million cubic metre reservoir, between Marcham, Steventon and East Hanney, would present more problems than housing developments to local communities.

Earlier this month, Oxfordshire County Council slammed the plans, claiming they were built on miscalculations.

Director of planning Susan Halliwell said she had significant concerns over Thames Water’s population forecast and warned the project would have "substantial environmental, transport and landscape impacts in southern Oxfordshire, both during construction and when in operation".

Plans for the artificial lake were thrown out by the Government in 2010, but Thames Water has been rebuilding its case since.

In a statement, the company said: “Our plan will always be based on the best available information.

"Since we provided our draft plan to Defra in 2017, new information has been published, such as the forecasts for population growth.

“We will take account of this and other information, together with all the consultation responses, to ensure we have a robust plan to provide a secure supply of water to our customers.”

Earlier this week the Angling Trust came out in favour of the controversial plans, saying building work should go ahead immediately to protect chalk streams in times of drought.