The problem with this type of thing is intent.
How do we prove intent to deceive?
Lying is not simply stating incorrect information. It is intending to deceive by knowingly stating incorrect information. It is not easy to prove what someone knew.
What if they were misinformed by a third party that may or may not have an agenda? Under these circumstances the politician is not lying and believes they are telling the truth even though the information they uttered is wrong. Do you go after the third party? Does this then give the politician a mechanism to evade charges using fall guys?
I absolutely believe that people like Bojo should be held to account. In his case there was plenty of evidence. It should also be acceptable for the opposition to state that they were lying in the commons without facing repercussions.