Last Night's TV - Storyville: Mandelson: the Real PM? BBC4; Turn Back Time: the High Street, BBC1

Prince of Darkness is in the thick of it

You've got to stop acting in such an imperial way," Tony Blair once told Peter Mandelson, according to the Prince of Darkness's own account in Storyville: Mandelson: the Real PM? On the evidence of Hannah Rothschild's film he doesn't appear to have taken the advice. Less fly-on-the-wall than lady-in-waiting, this account of five months in the life of the Business Secretary showed him to be imperial to the hilt. He could only have conveyed a greater sense of Roman grandeur if he'd been wearing a toga and shadowed by a figure whispering "You too will die" into his ear. At one point, the camera showed him eating a yoghurt: when he'd finished, he held the pot aloft wordlessly, obviously confident that a member of his sizeable retinue would make this troublesome object disappear. Hannah Rothschild, incidentally, wasn't whispering reminders of human mortality at him. She was – with perhaps more calculation than was always obvious on screen – gently nudging her subject's self-regard into the open so that we could see it unshadowed.

What was slightly surprising was how interesting it was given how little it revealed. Though granted close access to Mandelson as he conducted damage limitation during the election campaign what Rothschild was able to see and record had obviously been tightly controlled. There was no Gordon Brown, barring a few seconds during a couple of photo opportunities (the camera even dropped its head when he was around, like a skulking dog that hopes not to be noticed). No swearing or backbiting either, though the Thick of It setting – a gaggle of advisers meeting in neon-lit rooms – constantly led you to expect it. And when the election campaign crashed head on into that stroppy pensioner in Oldham all you got was shots of Mandelson reading the grim headlines. Yes, we saw the Business Secretary's legs as he changed into his dinner jacket for a Mansion House dinner, but that was a pantomime of exposure, not the real thing. The most candid account of what insiders were truly feeling – "privately he and two cabinet colleagues joke the campaign is 'futile, fucked and finished'" – was delivered by an on-screen caption, not recorded on film.

Mandelson, in short, gave away nothing except for details of his character that he can't help giving away, though that will may have been enough for connoisseurs of political guile. There was the brief pause after Mandelson had been asked whether he was "a kingmaker rather than a king", as he calculated there was nothing to be gained from acknowledging either before chuckling and answering, "No idea." There was the brilliantly ambivalent response he gave when asked for a thumbnail sketch of the then Prime Minister. "He's like a cross between a snowplough and a combine harvester... he just sort of drives through." Was this a compliment or an insult, or perfectly crafted to be both? And most delicious of all there was his taunting of George Osborne after the televised debates, a masterclass in public humiliation that left the current Chancellor lost for words. He eventually dredged up a replay a few weeks later and was unwise enough to deploy it, at which point Mandelson again put him down with a lethal ease.

This was no Yesterday's Men – a famous post-defeat documentary about old Labour that soured relationships between the party and the BBC for years – but it was alert to the bitterness of electoral defeat. As Mandelson talked witheringly of Cameron and Osborne's "sense of entitlement" and described them as ill-disciplined children running amok in a sweet shop, you could sense the frustration of a man who was about to have his keys to the confectionery store taken away from him. As the news came in – not as bad as had been feared but not good enough to keep Labour in office – Rothschild focused on what had been a bunch of grapes in a Labour office, every grape plucked and gone. That's what the end of office might look like, nothing left but the bare stalks and a sense of curiosity about how Mandelson will exercise his taste for power now that it's on the ration.

Turn Back Time: the High Street, BBC1's slightly unpersuasive exercise in immersive history, reached the Second World War this week, bringing in food shortages, queuing and night-time air raids. The bakers had been transformed into a British Restaurant – a kind of public-access canteen which served up dishes such as spam fritters and braised sheep's tongue – while the dressmaker was taking in old clothes for alteration and the butcher was trading exclusively in mutton and the odd bit of rabbit. What's unpersuasive is the pretence that the customers at these establishments are somehow subject to the rigours of rationing: "I'm going to starve!" one exclaimed, when she discovered just how little was available at the grocer's. No you're not, dear. If you're really peckish you can pop up the road for a Greggs sausage roll. Equally unconvincing was the indignation of one of the presenters when she discovered that the grocer had been keeping "specials" under the counter for favoured customers, sold on at a hefty profit. It seemed perfectly obvious that a bit of black-marketing had been structured into the programme from the very beginning, so her stern expressions of disapproval were presumably entirely bogus. Thank goodness for the row that erupted between the grocer's family and the bakers – a stress-induced little spat that had every sign of being completely authentic.