I would advocate for an independent body to fact check and regulate MP's, maybe a regulationary body like many professions have? There is the Law Society for Lawyers, and the NMC/GMC/HCPC for the healthcare professions. All of these professions have to adhere to a standard of conduct, both professionally and personally to remain on the register. This includes bringing the profession into disrepute, and lying to their clients/patients, which are both grounds for being struck off. There are obviously situations in which the MP's may have to omit information to the public on grounds of national security, but for everything else - it could be regulated. In the aforementioned professions, it is a requirement to stay updated on news/information from the professions, and if you give outdated or false information or advice, that can be grounds for misconduct. So MP's giving it the '"I honestly believed that was true" wouldn't fly, because they'd have to show they actually researched the issue before spaffing on about it.
Thoughts?