Last Night's TV: Help! My House Is Falling Down / Channel 4 <br/>Domesday / BBC2

Why, when all those dastardly bank bosses were made to sit in front of a select committee and confess their contribution to the economic crash, did the presenters responsible for the property TV show boom escape censure? How is it, after encouraging us all to splurge our easy credit on houses we could ill afford, that they've managed to segue straight into home improvement advice, now that none of us can meet the expense of moving again? First came Kirstie's Homemade Home, in which the relentlessly cheerful Kirstie Allsopp suggested homeowners spruce up their surroundings using techniques learnt from Blue Peter. Now we have Sarah Beeny with the B&Q-sponsored Help! My House Is Falling Down, for which Channel 4 manifestly failed to find anything other than a working title.

"Over the next few weeks," Beeny explained, accompanied by a sinister soundtrack that wouldn't have been out of place in a Tim Burton movie, "I'll be rescuing families whose lives and houses are literally collapsing around them." Is it possible, I wondered, that the people who've applied to appear on this show are the same ones who were too busy watching Property Ladder and dreaming of their second property to think about maintaining their first? Becky, the first of Beeny's onscreen clients, certainly struck me as the type.

Becky had persuaded her husband, Nick, against his better judgement, that they should buy a delightful 17th-century bakehouse somewhere north of their budget. Unfortunately, neither had bothered to check beforehand whether, say, the bakehouse's timbers might be riddled with woodworm; the bricks might be damaged by rain and the local species of masonry-munching bees; or the open well in the basement might, just might, be prone to causing a spot of damp.

While the perennially pregnant Beeny chided Nick for being a tasteless moron, and her specialist consultants doled out advice on re-pointing the walls and re-flooring the dining room, Becky blithely chuckled away – then demanded the installation of a luxurious master bedroom in the attic, using the remains of the couple's savings. Not only did this loft conversion come with a costly-looking chandelier, but Becky also allowed the children to paint the dining room purple without telling their father. Would anyone ever paint anything purple if they weren't being filmed for a home improvement show?

Beeny's next TV project, Beeny's Folly, will involve her putting her own money on the line when she buys a decaying mansion and tries to turn it into a posh, profitable wedding venue. I'm not exactly hoping she'll fail, just that she'll encounter a few major financial and structural difficulties along the way.

Full disclosure: as I am a debtor without much hope of buying a first home, let alone a second, my objectivity is compromised. Friendly property experts like Sarah Beeny make me clench things extra hard – my jaw, my buttocks, my remote control. As helpful as all her home improvement tips undoubtedly are, there's a part of me that wishes somebody would invite her and Kirstie Allsopp to Westminster, plonk them in front of some angry MPs, and force them to say sorry.

Property ownership was an even more fraught business in the 11th century than it is in the 21st. Being the self-pitying sort, it heartened me to learn that a Saxon "villeyn" had things a lot worse than I do. These were men who owned the land they worked and the homes they built on it – until 1066, that is, when the Normans arrived and snatched it all. The Norman Conquest, insisted Dr Stephen Baxter of King's College, London, was "the greatest political and social upheaval in England's history". Once the landgrab was complete, some two decades later, William the Conqueror had every patch of property in England and its ownership recorded in the magnificent Domesday Book, which Baxter has spent one decade studying.

Why, he asked in his documentary Domesday, did William commission the survey in the first place – especially in 1085, when his knights were preoccupied with the possibility of a Viking invasion? Many historians argue that it was an aid to taxation, or a vainly comprehensive register of the King's power. But Baxter believes the book was propaganda, designed to airbrush the short reign of Harold Godwinson from history, and a way of giving Norman nobles the security of ownership of their new lands.

Whatever the truth, there's no doubt this was a fascinating period of history, but it's pricey to bring to life on screen. Unfortunately, the endless footage of random green fields, barely intelligible 11th-century calligraphy and Baxter wandering around medieval ruins speaking intensely to camera was all a little bit too Open University. The production couldn't even afford the few modest historical re-enactment sequences that graced its sister show, Robert Bartlett's The Normans. The BBC has just proved that history can be done brilliantly on radio (I speak, of course, of A History of the World in 100 Objects). That might be a better place for Baxter's lecture.