An inquiry into questions raised by the so-called ClimateGate affair will release its conclusions on Wednesday.
The Independent Climate Change Email Review was commissioned by the UK's University of East Anglia following the hacking of emails from its servers.
Climate sceptics allege that the emails undermine the integrity of researchers at the university's Climatic Research Unit and of climate science in general.
Two previous reports found issues in the unit, but no deliberate deception.
At the end of March, a report from the House of Commons Science and Technology Committee said the Climatic Research Unit (CRU) should be more open and transparent and must comply with Freedom of Information laws.
But it found no evidence of malpractice.
And in April, a second inquiry looking at scientific output from CRU found no evidence of malpractice, but criticised the sometimes "messy" practices within the unit and suggested closer liaison with professional statisticians.
Both reviews were criticised in "sceptical" circles as superficial and lacking in balance.
The unit has played a key role in building datasets of global temperatures, which are key to understanding modern-day human-induced climate change and widely cited in the influential assessments from the Intergovernmental Panel on Climate Change (IPCC).
The third review, chaired by former civil servant Sir Muir Russell, is likely to prove the most influential of the three and has spent much of its time gathering and sifting comments sent in by interested parties.
These include working climate scientists, including some who have collaborated closely with the unit and its former director Phil Jones, and prominent critics.
The Canadian blogger Stephen McIntyre, who runs the influential website climateaudit, called the independence of panel members into question - an issue that Sir Muir rejects.
On CRU itself, his submission to the inquiry said the unit had manipulated and withheld data in such a way as to distort temperature records.
"The manipulation includes (but is not limited to) arbitrary adjustment ('bodging'), cherry picking and deletion of adverse data.
"The problem is deeply rooted in the sense that some forms of data manipulation and withholding are so embedded that the practitioners and peer reviewers in the specialty seem either to no longer notice or are unoffended by the practices."
However, Professor Raymond Bradley, an eminent climatologist from the University of Massachusetts, said he had "the greatest respect for (the CRU team's) scholarship, insight and scientific integrity, and I have seen nothing in the stolen emails that changes this opinion".
The hacked emails and other documents emerged shortly before the Copenhagen climate summit, and the episode was seen in some quarters as an attempt to wreck the chances of a meaningful global treaty.
"The theft was a political act, and your inquiry should be fully aware of the context in which you are operating," Professor Bradley told the inquiry.
The panel's investigation will:
- Examine the hacked e-mail exchanges, other relevant e-mail exchanges and any other information held at CRU to determine whether there is any evidence of the manipulation or suppression of data which is at odds with acceptable scientific practice
- Review CRU's policies and practices for acquiring, assembling, subjecting to peer review and disseminating data and research findings
- Review CRU's compliance or otherwise with the university's policies and practices regarding requests under the Freedom of Information Act
- Review and make recommendations as to the appropriate management, governance and security structures for CRU and the security, integrity and release of the data it holds.
It will not review the accuracy of the science emerging from CRU, or of climate science itself.
On Monday, a review commisioned by the Dutch government into the IPCC's projections of climate impacts found "no errors that would undermine the main conclusions" - that man-made climate change poses a significant threat in many regions of the world.