I'm not a lawyer, but my understanding is that freedom of expression does not have the quality control that academic freedom has, for instance. People get to lie. There may be parliamentary rules that I'm not aware of—you're more aware of those than I am—but freedom of expression does not come with quality control. That's the first thing.
It's important to note as well that when people say things that aren't true, they're not necessarily lying. Not to be too much of a philosopher, but we say lots of untrue things sincerely out of sincere error all the time. It's important to disambiguate between misinformation, which might be a sincere error, and disinformation, which is an intentional lie.
Obviously, though, the consequence of both misinformation and disinformation is a confused public who can reason badly about important matters of the day.
I will add—this may be, again, too philosophical a point—that people can also say true things that are selective and will mislead people. Utterances in general have consequences, whether they are true or false, or sincere or insincere.