New files to be released as part of the Peter Mandelson scandal will reveal 'embarrassing' messages between Labour ministers and the disgraced peer, it has been claimed.

The documents, set to be published when MPs return to Parliament after their half-term break, will reportedly show some ministers were 'sucking up' to Lord Mandelson.

Earlier this year, MPs ordered the publication of documents relating to Lord Mandelson's controversial appointment as Britain's ambassador to the US.

A first tranche of files was published in March and a second batch of documents is expected to be released next month.

Keir Starmer has been left reeling by the Lord Mandelson scandal and is now fighting for his political future following Labour's dismal local election results.

The publication of the next set of Mandelson files will heap more pressure on the Prime Minister, but insiders claimed there is no 'smoking gun' in the latest documents to bring down the Government. 

A source told The i Paper: 'The messages are more embarrassing than anything else and reveal a far too cosy relationship between some ministers and Lord Mandelson.'

Wes Streeting, who quit as Health Secretary this month after losing confidence in Sir Keir's leadership, has previously released his own messages with Lord Mandelson.

In February, Mr Streeting published his private WhatsApp messages with Lord Mandelson in a bid to show he had 'nothing to hide' about his relationship with the peer.

They revealed that Mr Streeting had congratulated Lord Mandelson on his appointment as US ambassador in December 2024.

The messages also showed how Mr Streeting had complained to Lord Mandelson in March last year that the Labour Government had 'no growth strategy at all'.

When Lord Mandelson messaged Mr Streeting that 'the government problems do not stem from comms', the then-Health Secretary replied in March 2025: 'Quite.' 

Mr Streeting went on to add: 'There isn't a clear answer to the question: why Labour?', to which Lord Mandelson said: 'The government doesn't have an economic philosophy which is then followed through in a programme of policies.'

In the same exchange, Mr Streeting also expressed fears that 'we're in big trouble here' he will be 'toast at the next election', due to the strength of the pro-Gaza vote in his Ilford North seat.

In further messages in July last year, Mr Streeting was revealed to have discussed with Lord Mandelson as to whether the Government should take a tougher stance on Israel.

Earlier this month, Parliament's intelligence watchdog criticised the Government for redacting documents related to Lord Mandelson's appointment 'far too broadly'.

The Intelligence and Security Committee (ISC) has been given the final say on what is published as the Government complies with the 'humble address' motion demanding the release of all files relating to Lord Mandelson's appointment.

The ISC said it has made its final decisions on redactions to 337 documents connected to the appointment on national security grounds.

But in a statement, the ISC raised 'concerns' about wider redactions, including individuals' personal data, email addresses and the identities of junior civil servants.

The committee said it did not think the motion passed by the House of Commons demanding documents related to Lord Mandelson's appointment allowed redactions 'other than on grounds of prejudice to UK national security and international relations'.

The ISC also suggested redactions on non-security grounds were 'being applied far too broadly', and accused the Government of withholding documents despite not having 'the authority to do so'.

Darren Jones, the Chief Secretary to the Prime Minister, said the Government has taken the 'normal approach' to redactions, telling MPs this month it would not be in the public interest to publish the names and contact details of junior officials.