The $30 million toe in the water

The UK Government is preparing to publish thousands of documents related to Peter Mandelson's disastrous appointment as US ambassador. The documents, which are expected to be released today, include messages between Mandelson and ministers, aides, and other government officials.

They are believed to include indiscreet criticism of Prime Minister Keir Starmer by his own senior team. The Government was forced to agree to the disclosure after a massive Labour revolt in February, which almost saw Sir Keir kicked out of No10.

Some insiders fear that Andy Burnham could seek to exploit the premier's woes for his leadership bid by claiming the Mandelson documents show Westminster is broken.

An echo of Sydney's 2024 institutional buy-up

The Government was forced to agree to the disclosure by a massive Labour revolt in February - which almost saw Sir Keir kicked out of No10. Some insiders fear that Andy Burnham could seek to exploit the premier's woes for his leadership bid by claiming the Mandelson documents show Westminster is broken.

Touring broadcast studios this morning, Health Secretary James Murray said: I think the level of transparency is going to be unprecedented.

The volume of information that's going to be put out is unprecedented. Its right we do that. We have been very clear that the appointment of Mandelson was wrong.

Who is the unnamed buyer?

The Government has said it has only withheld documents where requested by the police, and all other documents will be published. Several documents have also been redacted, either to remove personal details such as the names of junior officials, or on national security grounds.

Redactions on national security grounds were agreed with Parliament's Intelligence and Security Committee following a compromise with MPs to head off a backbench rebellion on the demand for documents.

Last month, the committee raised concerns that the Government was applying redactions too broadly, and cited the UKSV vetting file as an example of documents being withheld without Parliament granting ministers the authority to do so.

What auditors flagged in the May filing

A first tranche of documents, released in March,showed Sir Keir was warned in a due diligence document about Mandelson's long-standing links to paedophile financier Jeffrey Epstein.

The second set of documents is expected to include messages between Mandelson and ministers and Government advisers, including Sir Keir's former chief of staff Morgan McSweeney.

It is not clear how many of Mr McSweeney's exchanges with Mandelson have survived, after his mobile phone was sotlen last year.