Mandelson files show no mitigation of security concerns over US appointment

Exclusive: Papers to be published on Monday cast doubt on assurances provided by senior Whitehall officials

• Embarrassing WhatsApps, but no vetting report: what will be in the new release of Mandelson files?

A trove of government documents about Peter Mandelson contains no record of any measures taken to mitigate serious security concerns over his appointment as Washington ambassador, the Guardian has learned.

Multiple sources who have seen or been briefed on the files, which will be published on Monday, say there is no detail about any steps put in place to deal with flags raised about his associations with senior figures in foreign states.