How dare LH try to make IB say inadvertently when we all know that would be a lie?
Because it is basic tenet of the House. You don't call anyone a liar and if you do the meeting is cloised. He explained it all, repeteatedly, at the time. "Just say 'inadvertently' and we can continue this much needed discussion. Don't force me to have you removed and the debate closed"
It's not that he supports Johnson, just that this is one of the non negotiable rules of the House. It is there to protect Members from various legal allegations, to ensure freedom of speech etc .
IB could have said "apparently inadvertently" and that would have been enough... and he, like all other MPs, know that!