(CNN) Christopher Steele, the former British spy who compiled a controversial dossier on President Donald Trump, has been told information on him that had originally been redacted has now been declassified and will be included in the Justice Department inspector general's report Monday, according to two people familiar with the matter.

Steele was informed before midnight in the UK on Sunday that the additional material would be contained in the report's final draft, according to a source close to his corporate intelligence company Orbis. Steele was not told what the new information would be and was not given an opportunity to respond before the report's publication, the source added and a second source confirmed.

Attorney General William Barr made the unusual decision to declassify additional information on Steele, The New York Times first reported.

Steele spent two days meeting with representatives of the Justice Department in London to voluntarily cooperate with their probe in June this year and followed up with further conversations via Skype. Orbis also provided the inspector general with access to its internal documents and memoranda of its meetings with the FBI since the firm's relationship with the bureau began in 2013.

Orbis had a chance to review 50 pages of the report pertaining to Steele and his firm last week and highlighted numerous mistakes and inaccuracies, in particular with Steele's characterization in some parts of the report as a "confidential human source" rather than as a contractor, according to material prepared by Orbis and seen by CNN.

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