The government will publish the Mandelson Files at around 14:30 today, releasing more than 1,000 pages of material on Lord Mandelson's appointment and his time as ambassador to Washington. Darren Jones is then due to make a statement in Parliament, turning the document dump into a fresh political test for ministers as the papers go public.
The bundle is far larger than the first tranche issued in March, which ran to 147 pages, and it is being printed and bound as three volumes. More than 160 pages are made up of Lord Mandelson's text messages and WhatsApps, giving the release a more intimate view of how the government handled one of Labour's most influential figures at the time.
Ministers are selling the publication as an exercise in unprecedented transparency, with the Prime Minister's official spokesman saying every government department had been involved in meeting the terms of the humble address and describing it as the largest ever response to this kind of demand. The government has also said it will provide a clear explanation of how the documents were gathered and why any redactions were made.
That promise will only go so far. Some of the material is likely to be blacked out on national security grounds, especially where military or intelligence content is involved, and the final release may still leave readers wondering what was left out. The documents are expected to offer an internal look at how Whitehall works, but also to show how much of the record can remain hidden even in a publication billed as unusually open.
The papers are tied to a humble address from Parliament demanding documents on Mandelson's appointment and tenure in Washington, and the scale of the response reflects how many parts of government were drawn into the process. The Washington embassy is described as so large and so closely connected to the UK-US relationship that the files reach deep into Whitehall, which is why today's release is likely to attract attention well beyond those who followed Mandelson's period in office.
For all the talk of openness, the real story may be in what survives the redactions. By this afternoon, the government will have handed over the biggest Mandelson documents release yet, but the part that matters most may be the part officials still decide cannot be seen.
