The Government is working to declassify more than 100 secret documents detailing discussions that took place between Tony Blair, Gordon Brown and George Bush in the run-up to the Iraq war. The Independent understands that, in an unprecedented move, a cache of notes from Mr Blair to Mr Bush, records of telephone conversations and meetings, as well as up to 200 minutes of cabinet-level discussions are to be published in the new year.

The release of the documents, which is likely to be in the next few months, will clear the way for Sir John Chilcot’s Iraq Inquiry to publish its long-awaited report into Britain’s involvement in the conflict.

There had been fears that Mr Blair and the US authorities would block the release of the confidential papers, which are said to provide an intimate picture of how decisions were made in the lead-up to war.

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On Sunday, a government source said that “good progress” had been made towards declassifying many of the records. “The intention is to be as open as possible,” they said. “There is an ongoing process of declassification, which is attempting to strike a careful balance to ensure that you are not setting a legal precedent that could oblige you to publish other documents in the future or damage national security.”

The process is being led by the Cabinet Secretary, Sir Jeremy Heywood, and is expected to be completed “within the next few months”. David Cameron, Nick Clegg and other senior ministers do not know what the documents contain because they refer to discussions that took place under the previous government. A final decision on what to release will be made by Sir Jeremy.

Once declassified, the documents will be passed to Sir John, who heads the Iraq Inquiry. He has already had access to the material but wants to be able to refer to it in his final report.

Although no final decision has been made, the documents are likely to be made available to the public, either by the Government or on the Iraq Inquiry website. “There are likely to be some redactions – but only where absolutely necessary,” the government source said.

Publication of the documents will allow the Iraq Inquiry to complete its final task of contacting those people who are due to be criticised and allow them to put forward a defence. That process could take several months, but it is now possible that the inquiry could report by the end of 2014 – five years after it was set up by Mr Brown.

A Cabinet Office spokeswoman said last night: “The Government is currently engaged in discussions with the [Iraq] inquiry which the inquiry recognises raises difficult issues, including legal and international relations issues.

“As the exchange of letters between government and the inquiry shows, these issues are being worked through in good faith and with a view to reaching a position as rapidly as possible. The inquiry should be allowed to publish its findings and we should not pre-empt the content of the report.”