Robbins says officials considered withholding Mandelson vetting files from parliament

However, according to Robbins, it was true that top officials in multiple departments were weighing whether the documents should be disclosed to a parliamentary committee to comply with a motion known as a “humble address”.

That motion, passed in February, required the government to release “all papers” relevant to Mandelson’s appointment. The wording of the motion referenced documents “including but not confined” to various branches of government, including UK Security Vetting (UKSV).

The motion made an exception for papers prejudicial to national security or international relations. It said these should be released to the ISC, which would determine whether they should be made public.

In his testimony, Robbins said the wording of the motion was “a bit inconclusive about exactly what parliament wanted of the government in connection with vetting”. He said there was “live conversation” and “debate” among top officials at the Cabinet Office, Foreign Office and other departments about disclosure.

Government sources have told the Guardian that it was always the intention of top civil servants at the Cabinet Office to release the document to the ISC. A version of the document is understood to have been shared with the committee.

UKSV is an agency within the Cabinet Office. Robbins described the discussions as a “debate about whether the Cabinet Office open their own safe”, and recalled being briefed that officials in that department were “very worried” about doing so.

“In the end they chose to do so,” he said in reference to the opening the safe analogy. “I would still have wished that they didn’t, not because of what has happened to me but because of all of the factors I’ve tried to lay out to you this morning.”

The debate among officials about whether to release the document occurred over almost three weeks. Others who were party to the discussions included Antonia Romeo, the cabinet secretary, and Cat Little, the top civil servant in the Cabinet Office. Starmer was initially left in the dark about the debate and was informed that security officials had denied Mandelson clearance only on Tuesday last week.

The Cabinet Office maintains there was no undue delay because the civil servants were engaged in a process of “expedited checks” aimed at informing the prime minister as quickly as possible.

According to one source familiar with the debate, there were fears among at least some officials that there might be an attempted “cover-up” and the document would never see the light of day.

However, after the Guardian revealed the details of UKSV’s advice that Mandelson should not get developed vetting clearance on Tuesday, there appears to have been a decision to share materials with the ISC.

In reference to the leaks to the Guardian, Robbins said: “I hope that they’re being investigated very rigorously and that prosecutions will result, because this is a grievous breach of national security.”

Jones’s spokesperson did not respond to a request for comment about his claims that the Guardian story was “not true”.

Asked last week if he had misled the public, a source close to Jones insisted that his answer was “clearly focused on the official government response to the humble address, which he makes clear later in his answer”.