After the Cambridge Analytica whistleblower, Mark Zuckerberg is facing a new nemesis in Britain. Martin Lewis, founder of the popular U.K. personal finance website MoneySavingExpert.com, says he is suing Facebook Inc. for defamation over dozens of unauthorized adverts that use images of him. As is so often the case, the social media giant's response was pretty shopworn: "We do not allow adverts which are misleading or false on Facebook." This statement is self-evidently misleading and false. If dodgy ads weren't allowed on Facebook, they wouldn't be on Facebook. And they are. But it doesn't stop Facebook from using it repeatedly. Zuckerberg's company puts the onus on users to report the ads, and promises to take them down. Martin Lewis claims he does exactly that, yet they show up repeatedly - some of them scams. And, as my colleague Zeke Faux has reported, Facebook has cozied up to disreputable advertisers in the recent past. The problem lies at the heart of Facebook's business model. The handling of pretty much all of its ads is automated. It has only 25,000 employees, and each one generates $1.6 million in sales on average. That's how it can afford to pay a median salary of $240,430. Back in October, Facebook said it was hiring another 1,000 people to review and remove ads. But that workforce is still reactive. It removes ads that are already out there, and people like Lewis are still encountering the problem. It tries to vet ads in advance using machine learning. But that's a far from perfect technology. Good content is sometimes blocked while damaging posts and ads continue to surface. Amazon.com Inc.'s median salary of $28,446 raised the hackles of low-pay campaigners last week; understandably so given the vast worth of the company. But Zuckerberg could take a leaf out of the Jeff Bezos book. While Facebook's median salary is almost 10 times bigger than Amazon's, it badly needs to employ more eyeballs on not-such exalted wages to fix the problems it can't catch with automation. At the very least, each advertiser should be vetted in advance - as Facebook has promised to do with political ads. This will reduce profitability, but a company whose lifeblood is user data and advertising can only sustain so many hits to its reputation. It's certainly shaping up to be an interesting week for the company in London. British lawmakers get to grill Chief Technical Officer Mike Schroepfer on Thursday. It will be a very different affair from Zuckerberg's two sessions on Capitol Hill, where senators were given five minutes and house members just four minutes apiece. Zuckerberg was able to offer responses that were often as evasive as the response to Martin Lewis's complaint. The British committee consists of just 12 members, who will each have more time and be able to ask pointed follow-up questions. Parliament's special committees have a pretty decent reputation for holding companies to account, and Europe has made much of the running on tackling the powers of Silicon Valley. Until Zuckerberg makes some profound changes to his workforce structure, don't expect it to ease up.