The huge legal costs incurred by Gloucestershire County Council over the controversial incinerator scheme has been attacked by Stroud Green Party members.

Last month the county council was ordered to release more financial details about the £500 million waste incinerator currently under construction.

The Information Commissioner's Office (ICO) ruled that the county council wrongly withheld some of the information relating to its agreement with Urbaser Balfour Beatty ( UBB) to develop and run the Javelin Park incinerator next to the M5 at Haresfield.

The ICO said the council had disclosed the majority of the information requested, but not sections of a report "value for money and affordability analysis" written by Ernst & Young LLP.

The Green Party says the county council has spent over £400,000 with Eversheds LLP in relation to Javelin Park since 2015, with invoices from April 2017 showing at least £200,000 related to the Information Tribunal appeal.

Tim Davies, a Green Party member and open data campaigner, said the council was about to commit taxpayers money to another costly appeal against the Information Commissioner's decision, trying to keep information secret, he claimed.

Mr Davies said: "As a Gloucestershire resident who is going to pay for this contract, I want to see what has been agreed in my name, I want to see what value for money is being provided. It should not be a matter of trust, it should be a matter of fact.

"It is in GCC's interests, residents interests and the companies working for local authorities interests to make these contracts and payments open and transparent."

County councillor Rachel Smith (Green, Minchinhampton) said: "Gloucestershire County Council have a habit of losing appeals to the Information Commissioner's Office. How many more hundreds of thousands of pounds are they going to spend hiding information from their residents and taxpayers."

In response, Cllr Nigel Moor, Gloucestershire County Council cabinet member for fire, planning and infrastructure, said: "The contract information which hasn't been shared so far is about the costs and assumptions that have been used to work out the value for money of the energy from waste facility.

"We accept that people are interested in these contract details but if we share them at this time it will significantly prejudice the commercial interests of the council, local taxpayers and UBB.

"As contracts are currently being negotiated we cannot put information into the public domain that would weaken our hand. For example for the sale of electricity a reduction of just £5 in what we can achieve per unit of electricity could see us lose out to the tune of £14 million over the 25 year contract. Money we want to invest in essential council services.

"Most of the legal costs mentioned by the Green Party are about an old case from 2013. The amount of local taxpayers' money that could be put at risk runs into the tens of millions - that's why we've spent a few thousand pounds defending the ICO ruling for what we believe are the best interests of Gloucestershire people."