Consultants were commissioned by York Council officers at the start of the year to carry out a study to assess the impact of the proposed sale of the Union Terrace car and coach park.
The controversial scheme, which would see the site sold in a £3.2m deal to York St John University to expand its campus, has provoked a bitter row between rival factions on the council.
York Council has now published the report which was compiled by consultants at Halcrow in a bid to end the political in-fighting.
The authority’s chief executive, Kersten England, has confirmed that the university’s Vice-Chancellor, Prof David Fleming, had approached the council at the end of 2010 about the possible sale.
However, a question mark still remains over who actually commissioned the consultants from Halcrow in February to work on the report, which cost more than £9,000.
Members of the previous Liberal Democrat administration, who lost control to Labour in the May local elections, remain adamant that it was not their decision to ask for the study to be undertaken.
But the leader of York Council, Coun James Alexander, claimed that the Liberal Democrats were “political opportunists in opposition”.
He said that there was evidence that the Lib Dems had backed the scheme, but had delayed it until after the election.
Coun Alexander maintained it was “hard to believe” that the new leader of the Lib Dem group, Coun Carol Runciman, knew nothing about the sale of the car park while her party was in power.
Coun Runciman, who was the council’s deputy leader up until May, confirmed she had informal discussions with Prof Fleming last September.
But she stressed that the Liberal Democrats had always opposed the sale of the coach park amid fears over the impact it would have on the city’s retail sector if visitor numbers dwindled.
An extraordinary council meeting which has been called for by the Liberal Democrats will be held on Thursday.
Senior Labour councillors are then due to discuss the proposed sale during a cabinet meeting to be held on the same day, when they are expected to agree for a six-week public consultation to be held.
The plans to sell off the coach park have sparked a public outcry, and campaigners have collected more than 15,000 signatures on a petition against the proposals.