Sweatbox day. In the room where the foreign affairs select committee held its morning interrogations the heat was hellish. Morgan McSweeney tried to open a water bottle but was shaking so much, he couldn’t manage it. A clerk had to help.

Mr McSweeney’s right eye started to twitch, like that of Clouseau’s boss in the Pink Panther films. His left elbow convulsed. He crossed his arms emphatically, hugging himself in a strait-jacket.

Here, finally, was Labour’s former chief poisoner, the fabled genius who created our dud of a PM. He proved an underwhelming tiddler, size of a jockey, with a high Irish voice. He wore a cheap shirt and a suit surely from M&S Schoolwear (‘uniforms that last’). Under the table he couldn’t stop fidgeting. The feet were tapping away like something from Riverdance. McRasputin, O’Svengali, or whatever you call him, was a bag of nerves.

In Oz the booming wizard is eventually found to be merely a quavery old man who created an aura for himself. Ditto McSweeney? Trembling and squeaky, he begged to be believed, a gurrier up before the magistrates.

Committee chairman Dame Emily Thornberry – herself denied a government job to make space for Sir Keir’s slithery pal Lord Hermer – relished the moment. Dame Emily wore a sequinned aubergine jacket. Her dimples were deep enough to serve as salt cellars. Horatia Rumpole.

She had Mr McSweeney in trouble when she asked about No 10’s attempt to bung an ambassadorship to Matthew Doyle, a press officer it wished to ‘exit’ (i.e. sack). Mr McSweeney claimed this was mere ‘duty of care’.

Dame Emily, gurgling, asked if he had not heard the phrase ‘jobs for the boys’. Was the attempt to find a diplomatic posting for Doyle not ‘a little odd or shameful?’ Why, if it was duty of care, was Sue Gray not offered an ambassador job when she was dumped as chief of staff?

Mr McSweeney replied that Useless Sue was instead sent to the Lords.

Peter Mandelson was disowned. Once they were dining partners, at Peter’s home and smart restaurants. Now Mr McSweeney could only refer to him by the surname. ‘Mandelson’ was spat out like an olive stone. He denied MPs’ suggestions that dear Peter was ever a ‘hero’ or ‘mentor’, but did admit he had been a ‘confidant’ and adviser. He insisted that Lord Mandelson did not tell him the truth, and that this had been ‘a knife to my soul’.

Oh come off it! This was Peter Mandelson, flesh-and-bones embodiment of silken half-truths. How could anyone be shocked by a few velvety Mandelsonian fiblets?

Mr McSweeney clutched his tight little ginger beard most piously about the practice in politics of malicious gossip. ‘Very, very corrosive,’ quoth our chaste Jesuit. ‘I don’t know why people do this.’ He was pink when he said this. It must have been the heat. Or sheer embarrassment at the hypocritical rubbish he was spouting.

Sir Philip Barton, former head of the Foreign Office, also gave evidence to the committee. Come some grievous day – many moons hence, we must hope – stonemasons will engrave a tombstone with the word ‘Here Lieth Sir Philip Barton – he kneweth nothing’. Sir Philip, 62, kept saying ‘I’m not being difficult’. Do people ever mean it when they say that?

Over in the blessedly air-conditioned Commons the whooping Opposition galloped ever tighter circles round Sir Keir Custer and his beleaguered government. One of the PM’s parliamentary aides, Jon Pearce (Lab, High Peak), sat sullenly on the back row, jiggling his legs, thrashing his head side to side. He looked miserable and does not seem to have shaved for days.

Few Cabinet ministers attended the debate as Kemi Badenoch tore into Sir Keir. Up first for Labour was Emma Lewell (South Shields). She felt ‘let down, disappointed, angry’ and complained that in the street she is shouted at as ‘a member of the paedo protectors’ party’. Voters felt that ‘something is not quite right’.

The trials continue.