Campaigners fighting to stop ash being dumped in a former gravel pit near Abingdon have received a boost - after an inquiry into the bid was extended.

The Government Office for the South East is reviewing Oxfordshire County Council's decision to let RWE npower dump thousands of tonnes of waste fuel ash from Didcot Power Station into Thrupp Lake, at Radley.

Campaigners including the Save Radley Lakes group say the council's decision was contrary to its own policy.

The deadline for a decision on whether the council acted correctly was due on Tuesday but civil servants have asked for more time to study the evidence.

Campaigners, who have been fighting the plan and submitted objections to the review, hope the delay may lead to a public inquiry being held.

While the assessment continues, an interim ban has been placed on preparing the lake to take the waste ash.

Linda Pasquire, of Save Radley Lakes, said: "We don't want to pre-empt any decision but we would like to see the planning application called in, so there is a proper inquiry into what has been going on.

"The holding order might only be a temporary stay of execution.

"In effect, the Government has received a large bundle of papers and reports to read, and the department has been hard pressed to look at everything it needed to in the period of three weeks.

"We remain optimistic that the Government Office for the South East will be looking at this with an unbiased approach.

"We hope that common sense will prevail so that a beautiful area such as Radley Lakes can be retained for future generations.

"It is a much loved area for the community to enjoy.

"I'm glad they are taking more time and hoping reason will prevail in favour of Save Radley Lakes campaigners and supporters.

"But we're not jumping up and down with joy just yet."

The holding directive which was imposed means the county council cannot permit the power station to begin preparing the site for fly-ash slurry by felling trees and draining the lake.

The application could be called in by the Secretary of State for Communities and Local Government, Ruth Kelly, if it is deemed controversial enough.

An inquiry conducted by a Government planning inspector would then be ordered.

Chris Cousins, head of sustainable development at Oxfordshire County Council, said: "It's quite normal for the Secretary of State to ask for more time to consider applications.

"We await the comments of Ruth Kelly before the situation moves on."

The Government Office for the South East could not say how much longer it needed to study the evidence.