Over 30 files covering the Labour Government's 1997 devolution policy – believed to contain splits on abortion and the powers of the Parliament – were set to be published on Thursday under the SNP Government's "15-year rule".
Some 400 other files, covering issues such as aviation, legal aid and child safety, were released after they were previously kept secret. However, the plan to put the devolution files before the public was stymied after the Scotland Office asked to inspect all the documents at the 11th hour.
The UK and Scottish Governments operate different policies on the opening up of historical records from previous administrations.
In Whitehall, files are released when they are 30 years old, a time period that is being reduced to 20 this year. In Edinburgh, following a decision by Alex Salmond's government, the records of the former Scottish Office can be released after 15 years.
Last week, a raft of files from 1997 – the first year of Tony Blair's Labour government – were made available by the National Records of Scotland. But files from the key policy affecting Scotland in that year – devolution – were missing from the list.
The Scotland Office, which replaced the old Scottish Office, intervened to stop the release of the 36 files relating to Blair's Scottish Parliament proposals. It asked to inspect the documents before making a judgment at a later date on whether they can be published.
Ministers in the Whitehall department will have the final say.
The issue is controversial as the files are highly likely to reveal Cabinet splits on the devolution policy. After Labour's landslide victory in 1997, heavyweight UK ministers were involved in debating the powers of the Parliament, a package that was then endorsed in a referendum.
However, newspaper reports from the time claimed some ministers were trying to reign in the ambitious proposals set out by Donald Dewar, at that point Scottish Secretary.
Former home secretary, Jack Straw, was believed to be sceptical of devolution and reportedly used the internal government debate to raise questions about Scottish public spending. The then Lord Chancellor, Derry Irvine, was also believed to be asking tough questions.
Of the files being inspected by the Scotland Office, one focuses on "departmental consideration of the legislative competence" of Holyrood, Cabinet papers and correspondence between ministers.
Another document focused on whether issues such as abortion should be devolved. Dewar famously lost the battle to have abortion included within the devolution package, following resistance from Cabinet colleagues.
Over 20 of the files relate to the referendum that set up the Parliament, while the contentious issue of the voting powers of Scottish MPs is also in the mix.
One source close to the Scottish Government said the Scotland Office was cautious about releasing the files as it could provide a "gift" to the SNP. Nationalists would leap on any idea that ministers in the Blair government watered down the devolution policy. Brian Wilson, who was a Scottish Office minister in 1997, said: "I am a supporter of maximum transparency and have no problem with anything that took place at that time coming into the public domain. It would be very strange if there had not been robust inter-departmental exchanges on such a significant piece of legislation.
"However, what is sauce for the goose is sauce for the gander. While reducing the release date for records to 15 years, solely in order gain access to this period, the Nationalists have treated current Freedom of Information legislation with cavalier contempt, routinely releasing what that suits them and refusing other applications."
SNP MSP Jamie Hepburn MSP said: "These files must be released. It has been 15 years since devolution and whatever the UK Government is trying to hide it is time to be open with the people of Scotland. The Scotland Office will be cheating Scotland of its history if it does not allow these files to be released.
"The material in these files is not just an important part of our history; it could be of importance to the current debate over independence."
A Scottish Government spokesman said: "The vast majority of archived files due to be opened in 2013 have been released by the National Records of Scotland. The Scotland Office asked for a number of files to be withheld from release, and it is now up to Scotland Office and UK Government officials to inspect the remaining unopened files. The Scottish Government has no objection to the release of these files."
A Scotland Office spokesman said: "Pre-devolution files of the Scottish Office are owned by the UK Government but managed on its behalf by the Scottish Government and National Archives of Scotland.
"The Scottish Government operates a 15-year release rule. Prior to release the UK Government departments examine file descriptions and, in some cases, files to ensure that they can be released lawfully and in accordance with UK Government information policy."
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