Morning sun shafted into the Boothroyd Room as Sir Olly Robbins unpacked an ominously large leather briefcase and started to put his side of the Mandelson crisis. Nature’s spotlights picked out this tall, thickset proceduralist who was so rashly sacked by Sir Keir Starmer.

Danger hour for the PM. Would establishment man Olly do the dirty? To a surprising degree, yes. And he hinted of more to come.

Soft-spoken Sir Olly described the mind-frying pressure he came under from Starmerite henchmen to approve Peter Mandelson as US ambassador. He also let slip, with a certain pleasure, that No 10 wanted a head of mission post for Matthew Doyle, Sir Keir’s unhygienic former spokesman. Good grief, Ambassador Doyle! What lunatic self-entitlement exists in Starmer’s No 10. That man was no more fit to be an ambassador than Basil Brush.

The Doyle disclosure generated laughter, one onlooker dropping his forehead on the desk in disbelief. Sir Olly drily admitted ‘it was hard to think of anything suitable’ for Comrade Doyle. Sir Keir sent Doyle to the House of Lords instead.

‘My office was under constant pressure,’ recalled Sir Olly, referring to near-daily nagging from the PM’s office to rush Mandelson’s appointment. No 10 had initially proposed doing it without any vetting whatsoever. Sir Olly’s predecessor, Sir Philip Barton, had blocked that stinky proposal but it had taken a face-to-face confrontation.

Richard Foord (Lib Dem, Honiton & Sidmouth) asked if it was true that Sir Keir’s former chief of staff Morgan McSweeney – cue some dark Mahler chords, please – swore at Sir Philip when telling him to get on with things.

Mr Foord is a cautious goose and would not repeat the rude word. The committee’s chairman Dame Emily Thornberry (Lab) is more of a vulgarian, however. Lo and behold, she blurted McSweeney’s alleged words: ‘Just f***ing approve it!’ Mr Foord looked as if he might faint. Sir Olly did not demur. The Hansard reporters ground their teeth and pressed on through the filthy blizzard.

Were there echoes, here, of the Blair years when Tony’s fixer Jonathan Powell told our then ambassador to America, Christopher Meyer, to get up the backside of the US President? What is it about Washington that makes Left-wing spin doctors swear?

Sir Olly was plainly still in a state of shock and grief about losing the Permanent Secretaryship for which he had toiled as a civil servant for quarter of a century. All that hellish work was then snuffed out with one swipe of Keir’s claws.

As you would expect from a former head of the Foreign Office, Sir Olly was diplomatic and wordy. But seething, too. 

He was indignant about having been sacked. Baffled as to why it had happened. He had been through the mincer. His ‘wonderful family’ had been affected and he was unable at present to sleep in his own bed at home, or even to go down the street to buy a cup of coffee, without hassle.

Once or twice he wobbled on the brink of emotion, threw his eyes to the ceiling and grimaced – a rueful dimple in one cheek, a quiver of his jowls.

Behind Sir Olly sat Dave Penman, head of the mandarins’ trade union. Mr Penman has been quiet so far in this fandango – noticeably quieter than when Tory governments were beastly to civil servants – but perhaps The Blob is at last turning on the Starmer regime.

‘Dismissiveness’: that was the word Sir Olly used to describe Downing Street’s attitude to the vetting. The security aces said there was a problem. Sir Olly, under pressure, let the appointment proceed and then kept the details to himself. And Sir Keir sacked him for protecting him.

Aphra Brandreth (Con, Chester S) wondered if Sir Keir was truthful when he told the Commons on Monday that Sir Olly failed to explain himself. Sir Olly: ‘I must reserve my position on that. I may need to rely on it later.’ A matter for his lawyers? Sounds ominous.