The Scottish Government has been accused of an "unacceptable news blackout" over the Edinburgh trams project after Transport Scotland released pages of heavily redacted documents in response to a freedom of information request.
The Labour party sought information from the government agency about why its officials were withdrawn from the project's management board in 2007.
The response contains whole pages and, in some cases, whole documents which are blacked out.
Labour will now ask the Scottish Information Commissioner to order full disclosure of the information it requested.
Kezia Dugdale, Labour MSP for the Lothians, said: "This level of secrecy is breathtaking. We need to know why ministers ordered Transport Scotland experts off the project way back in 2007.
"We need total honesty and openness on the trams. People cannot hide behind a marker pen, and those responsible for mistakes must be prepared to take full responsibility. The inquiry I have called for must have the power to compel witnesses to attend and produce paperwork. A news blackout like this is unacceptable."
Councillor Lesley Hinds, Edinburgh Labour's tram spokeswoman, added: "There are real concerns that even under freedom of information law, so much information is scored out. We need a rigorous, full inquiry to make sure they can get to the truth."
A Transport Scotland spokesman said: "A full account of the reasons behind the decision to withdraw Transport Scotland from the trams board was given to the Parliamentary Accounts Committee in March this year and the records of this are in the public domain. This information has been sent to the individual who submitted this request.
"With regard to this particular request, the sections withheld in our response related to other policy matters other than Edinburgh trams and we consider these sections withheld under the Freedom of Information guidance."