The revelation comes as more documents relating to Lord Mandelson’s appointment as US ambassador have been published.
Angela Rayner (Image: Getty)
Lord Mandelson said Angela Rayner was being used as “an instrument of destabilisation” against Sir Keir Starmer. The disgraced peer claimed former PM Gordon Brown “has it in” for Sir Keir Starmer and Chancellor Rachel Reeves and was using the then-deputy prime minister to cause unrest.
He made the comment in WhatsApp messages to Cabinet minister Pat McFadden in May 2025, which have been revealed as part of the publication of the latest documents relating to Lord Mandelson’s appointment as US ambassador.
Mr McFadden said: “Lot of manoeuvring here this week. Angela, Gordon. Doesn’t feel good for Keir.”
Mandelson files undermine confidence in democracy says Hunt
Referring to the Prime Minister’s former chief of staff Morgan McSweeney, Lord Mandelson replied: “I have spoken to Morgan a lot this week and last night I was direct with him – Keir is not leading from the front and Morgan is not organising the centre as it needs to be Gordon has it in for Keir (and Rachel) big time.
“He doesn’t seriously believe that Angela is an alternative but she is an instrument of destabilisation.
“I doubt he thinks Ed is fit for purpose but he is doing to Keir what he has always done to successive Scottish leaders.”
The messages came as Ms Rayner was at the centre of Labour leadership speculation following the leak of a memo she wrote setting out proposals for taxing the wealthy and just before Sir Keir faced a revolt over benefit cuts.
The revelation is part of the publication of the second tranche of documents related to Lord Mandelson’s appointment as US ambassador.
The disclosure of the files, including WhatsApps and emails, is an “unprecedented piece of Government transparency”, Downing Street said.
The documents were ordered to be published by the House of Commons in the wake of revelations about Lord Mandelson’s ties to paedophile financier Jeffrey Epstein.
It is the second batch of files relating to the Prime Minister’s ill-fated decision to give the prestigious Washington post to Lord Mandelson rather than a career diplomat.
The peer was sacked in September 2025 just nine months into the job when more details emerged about his friendship with Epstein.
Subsequent revelations in the Epstein Files led to a Metropolitan Police investigation into alleged misconduct in public office.
