The full cost of creating opposing studies looking into whether Oxford could be run by a unitary council has emerged.

Oxford city and Oxfordshire county councils have spent more than £70,000 between them on investigations they hope will disprove each other's claims.

While Oxford City Council maintains a city unitary authority should take over the running of all local services in the interests of local democracy, colleagues at County Hall vehemently disagree.

The Town Hall has spent £58,520 enlisting the help of the Institute of Public Finance and specialist financial experts Rita Hale and Associates to strengthen its case.

Last month, chief executive Brian Dinsdale received confirmation from the Department for Communities and Local Government that it accepted the bid met its strict criteria.

The county council spent £13,000 on consultants and publishing costs to prepare its counter-case and is confident it will prevail.

Both studies are now being examined by Government ministers. Mark Luntley, city council finance chief, said: "Oxford City Council has been clear from the outset that any unitary bid was dependent on the financial viability of the case.

"The best way to ensure financial credibility was to engage external, independent experts to prepare the case. We engaged the Institute of Public Finance to do this work and to date we have spent £35,720 on their services. IPF are acknowledged experts in this field.

"All financial information in the city's bid was prepared and verified by the IPF.

"We have also used Rita Hale and Associates to examine what would happen to the revenue support grant, and that has cost £22,800. Staff working on the unitary bid have carried out this work as part of their normal duties. The publishing and printing costs for this work have been minimal."

The IPF has calculated the total cost of scrapping the current two-tier system of county council and the five district councils, and replacing it with three unitaries - Oxford city, Cherwell and West Oxfordshire, and South Oxfordshire and the Vale - would be £27.1m.

That is £27m less than County Hall's estimate of what the set-up would cost.

County council leader Keith Mitchell argues that the move would never recoup its costs.

If the Government agrees with the plan, the new unitaries would be up and running by April, 2009. All county council assets would be divided between the three new councils.