Here we go again. Some of the public may have had enough of the Peter Mandelson scandal by now, and would rather the focus returned to things such as the Iran war and the cost of living crisis. But Westminster has barely started on Mandy. Can’t get enough of him. This one will run and run.

You can almost hear the groans from No 10. By now it has finally dawned on everyone that Mandelson was never going to be a success as the US ambassador even if he hadn’t maintained close links with Jeffrey Epstein and leaked insider information to a bank.

The Prince of Darkness was always going to fail as a Trump whisperer. Because the US president is immune to his charms. The Donald may hate people who publicly disagree with him but he also quickly tires of and has no respect for those who flatter him. He is too much of a self-absorbed narcissist. Interested only in himself. So Keir Starmer might just as well have stuck with Karen Pierce. Mandelson has always been a completely avoidable, self-inflicted wound.

But the show must go on. And so on Thursday it was the turn of Cat Little, the permanent secretary at the Cabinet Office and the civil servant tasked with assembling all the necessary paperwork to comply with the humble address, to appear before the foreign affairs select committee. Over the past year or so there have been countless briefings against Little by colleagues and government insiders. On Wednesday, No 10 issued a statement saying how brilliant she was. That will probably be the kiss of death for her. Downing Street has sacked almost everyone else, so it’s probably her turn.

Mind you, it would be a minor tragedy were Cat to be fired. Because she is a true performance artist. The civil servant’s civil servant. In years to come, students of public administration will write textbooks about her. Her 100 minutes before the committee will be required viewing. Cat’s USP is saying things that appear to be interesting on first hearing that turn out to be quite dull when you’ve had time to reflect on them. A talent that has taken her near to the top of the civil service.

Cat has never had an opinion of her own that she has chosen to share with other people. That would be more than her job is worth. Instead she has chosen to keep a record of everything. If she met Olly Robbins outside the gents’ toilet and he said the hand dryers weren’t working she would make a note of it. And then someone would keep a record of a record having been made. And if something were too confidential, too sensitive for a record to be made, she would be sure to make a document of no document having been made.

The committee is rather enjoying its time in the limelight cross-examining everyone with a walk-on part in Mandelson’s appointment. No one more so than the committee chair, Emily Thornberry, after her omission from the cabinet nearly two years ago. A dish best served cold. She has no qualms about making life difficult for Keir Starmer: in fact, she rather relishes it. And she is backed up by an unusually lively and on-the-ball committee of members, who – unlike Kemi Badenoch at PMQs – tend to ask the right questions.

It’s just that they don’t always get particularly illuminating answers. At least not from Cat, a woman who was born to say Little. Nominative determinism at its best. Time and again Cat declined to comment. There were things that were so secret it was more than her life was worth to divulge them. If she did tell the committee, then she would have to kill them afterwards.

Even so, the peanut was pushed ever so gently forward. She did rather contradict the evidence Olly had given on Tuesday that it had been the Cabinet Office which had suggested Mandy might not have needed developed vetting. Cat had seen the document trail and it appeared the Cabinet Office had always wanted UK Security Vetting to be involved.

She had no idea why Robbins might have got the opposite impression. Nor why he might have tried to prevent her from obtaining the UKSV vetting report in her role as “keeper of the humble address”. She was not a mind reader. And she had not kept a record of their conversation because this was one of those conversations they had both mutually agreed not to document. Her job was to push pens.

Everything after this was rather a blank. She had no idea why Olly would have come to the conclusion that UKSV was only “leaning” towards refusing security clearance for Mandy when the document flagged two red lights and an outright no. That’s assuming it did have two red lights, which she wasn’t able to confirm as that was above the committee’s pay grade.

She couldn’t even be sure Robbins had read all 10 pages of the report. He might have skipped the conclusion. It was also possible he hadn’t understood the significance of the red light code. He might also not have realised red was red. Sometimes red is scarlet. She couldn’t even confirm whether there were any material differences between what had been covered in due diligence and the UKSV report. Again, she would have to kill everyone.

Thornberry wondered why there had been a three-week gap between Cat finally getting her paws on the UKSV report and her handing it over to the prime minister. Here, Little was rather more forthcoming. There were some documents that were so confidential you couldn’t automatically assume Keir Starmer would have clearance. The prime minister may be the most powerful man in the country, but he still takes second place to the civil service. So Little had chosen to consult several lawyers to make sure Keir was allowed access. National security was at stake and you couldn’t always trust the prime minister.

Much of the rest of the session was a rather unhelpful to and fro. Questions were asked. Answers were in short supply. Just dead-bat no comments. That was out of the remit of the humble address. The committee would have to ask the person involved. Occasionally we got to hear of documents that might be made available later but, at the time of speaking, Cat could neither confirm nor deny whether they existed. She lived only for empirical data. The committee would have to wait and see. There was a parallel world out there full of infinite possibilities. Little gave a rare smile as Thornberry brought the session to a close. This had been her finest hour.