Keir Starmer has reversed his position on the handling of sensitive documents linked to Peter Mandelson’s appointment as the UK’s ambassador to the United States after mounting pressure from Labour MPs threatened to defeat the government in the Commons.

Downing Street has now agreed that Parliament’s Intelligence and Security Committee (ISC) will oversee decisions on what material can be withheld on national security or international relations grounds, rather than leaving the process solely in the hands of the Cabinet Secretary and the Cabinet Office.

The shift follows days of rising anger on Labour benches and an intensifying push by the Conservative opposition to force fuller disclosure through a so-called humble address motion, a parliamentary mechanism that can compel the government to publish papers. Several Labour MPs signalled they were prepared to back the opposition unless ministers accepted stronger parliamentary scrutiny of any redactions.

The documents at the centre of the row relate to internal government due diligence and vetting around Mandelson’s appointment, and to wider questions about what was known inside government about his past association with the late financier Jeffrey Epstein after Epstein’s 2008 conviction in the United States.

Ministers had argued that elements of the file could not be published in full because disclosure might damage national security, undermine the UK’s relationship with the US, or cut across a live Metropolitan Police investigation. Critics within Labour, however, said the initial approach amounted to the executive marking its own homework and risked fuelling public suspicion of a cover-up.

According to reports in The Telegraph and other outlets, the Cabinet Office is now expected to provide further material than previously planned, with the ISC playing a gatekeeping role over any claims that documents must be withheld.

The climbdown is being viewed at Westminster as the most serious show of internal dissent faced by Starmer so far in his premiership, with senior Labour figures among those pressing for the concession. The move is intended to head off a potentially damaging Commons defeat and to reassure MPs and the public that any secrecy will be justified and independently tested.

The ISC is a cross-party committee of parliamentarians with the ability to review sensitive intelligence and security material. While its proceedings are not public in the way that select committees’ hearings often are, it is designed to provide a measure of parliamentary oversight where classified or highly sensitive information is involved.

The political storm has grown alongside the unraveling of Mandelson’s position in public life. He has stepped down from the House of Lords and has been removed from the Privy Council amid the intensifying controversy. Police have confirmed an investigation in relation to the affair, though details of any potential offences have not been set out publicly.

Starmer has sought to draw a sharp dividing line between his government and Mandelson, telling MPs that he believed officials had been misled about the extent of Mandelson’s continuing ties to Epstein after 2008. In Commons exchanges reported by multiple organisations, the Prime Minister described Mandelson’s conduct in severe terms and said the government had referred relevant material to the police.

For Labour MPs who had threatened to rebel, the issue has been less about the principle of withholding genuinely sensitive information and more about who should decide what counts as sensitive. In public comments carried by the Evening Standard and broadcasters, critics argued that the ISC was the appropriate body to determine whether claims of national security or diplomatic harm were well founded.

The opposition has seized on the episode as evidence of poor judgement at the top of government and of weaknesses in the appointments process. Conservative leader Kemi Badenoch has argued that the original decision to appoint Mandelson created the security and reputational risk now facing the government, and the Conservatives have continued to press for maximum transparency consistent with the law.

The documents sought by MPs are understood to include communications involving Number 10, the Cabinet Office and senior figures around Starmer, including his chief of staff, Morgan McSweeney, as well as due diligence material connected to the ambassadorial appointment. The government’s earlier preference was for the Cabinet Secretary to oversee which papers could be released and which should be withheld, a stance that became increasingly difficult to sustain as the prospect of Labour MPs siding with the opposition grew.

The argument has also revived broader sensitivities inside Labour about the party’s relationship with prominent figures from the New Labour era, as well as renewed public anger around the broader Epstein scandal and questions about elite accountability.

While the government’s acceptance of ISC oversight may defuse the immediate parliamentary threat, it does not settle the central questions driving the dispute: what precisely was known about Mandelson’s links to Epstein, what was said during the vetting process, and whether any warnings were raised, or missed, before the appointment was confirmed.

MPs and officials will now look to the committee process and the government’s next publication of documents for evidence of how much information will enter the public domain and how robustly claims of national security or diplomatic sensitivity will be applied. Further developments are expected as the Metropolitan Police investigation progresses and as Parliament considers whether additional steps, including further motions or inquiries, are necessary.