Peter Mandelson’s 2005 general election warning to Tony Blair over Gordon Brown

Files released to the National Archives show that Peter Mandelson warned Tony Blair that tensions with his chancellor would need to be carefully managed during the election campaign

Former UK ambassador to the US Lord Peter Mandelson (Niall Carson/PA) (PA Archive)

Peter Mandelson warned Tony Blair not to allow Gordon Brown’s supporters to wreck Labour’s 2005 general election campaign from within, newly-released government files have revealed.

Relations between Mr Blair and his chancellor were close to breaking point in the autumn of 2004 as Labour prepared to try to secure a historic third successive election victory, with Mr Brown and his allies believing the then prime minister had reneged on a promise to step down towards the end of the party’s second term to allow him to take over.

The much-disputed pledge was part of the so-called “Granita pact”, which saw Mr Brown agree to stand aside to give Mr Blair a clear run at the Labour leadership following the death of former Labour leader John Smith in 1994.

Former UK ambassador to the US Lord Peter Mandelson (Niall Carson/PA) (PA Archive)

Files released to the National Archives in Kew, west London, show that Mr Mandelson – who had long been one of Mr Blair’s closest allies – warned him that such tensions with his chancellor would need to be carefully managed during the election campaign.

Before leaving for Brussels to take up the post of Britain’s EU commissioner, the former cabinet minister said one of the challenges would be “agreeing where [Gordon Brown’s] people can be included without giving them a veto or scope for insider demolition”.

He said that while Mr Brown would want to inherit a healthy Commons majority when he did eventually take over, he would not want Mr Blair to get the credit.

“A big issue will be you personally. The media will want to bring pressure on you to a new level of intensity. Next door [Mr Brown] will want a good majority but will not want you to do well,” he wrote.

In the end, the two men were able to patch up their differences sufficiently to campaign together, with Mr Blair even buying the chancellor an ice cream at one event. But the tensions quickly re-emerged once Labour was back in office.

Mr Mandelson - who later served as UK ambassador to the US under Sir Keir Starmer’s government before stepping down over his links to Jeffrey Epstein - also stressed the need to woo “what passes for the ‘left’ media” after the bitterness over Britain’s involvement in the 2003 invasion of Iraq, the files revealed.

To that end, he said Alastair Campbell – who had stepped down as No 10 communications chief amid controversy over the government’s infamous dossier on weapons of mass destruction – should be kept in the background.

“You must be conscious of the need to create reasons for them to come back on side. Avoid things that will antagonise them (therefore be careful about AC – he is indispensable but must be equally invisible),” he said.

The files also show that officials encouraged Mr Blair to strip deputy prime minister John Prescott of his departmental responsibilities for communities and local government once the election was out of the way.

Mr Prescott was resisting the move, fearing he would be accused by the Tories of not having a proper job.

However the cabinet secretary Sir Andrew Turnbull expressed concern that he could hang on to some of the departmental elements, leading to more administrative turmoil in Whitehall.

“I understand that the DPM has suggested that, if he leaves the current department, he should nevertheless take the housing and planning portfolios with him. I understand also you are resisting this. I strongly urge you to keep doing so,” he wrote.

“The worst outcome would be to allow him to break up the department yet again. I think it would be better to leave him where he is rather than create a set of artificial boundaries.”

In the event, Mr Blair waited another year before acting, finally removing Mr Prescott’s entire departmental portfolio after he had been politically weakened by the disclosure that he had been having an affair with his secretary.

Sir Andrew was also scathing about the calibre of junior ministers coming through the ranks, saying they needed more training if they were to do their jobs effectively.

“If you think of yourself as a football manager who has no money for transfers and is reliant solely on graduating people through the academy, you have cause to be worried,” he wrote.