That's not the point of concern. The real issue is the prime minister's utterly anodyne and cowardly response. He needed to point out that such a law would contravene principles of free expression and he abdicated his responsibility.
It's PMQs, what kind of response would you expect - a PM isn't going to make policy on the hoof and there isn't really any need to clarify that you aren't going to make a policy change that you ... err have no intention of making.
I actually listened to the question and the PM's answer was largely a condemnation of islamophobia, which I hope we can all agree with. And the desecration of texts (whether religious or otherwise) can, under certain circumstances, be considered a hate crime and an aggravating factor. See what happens if you graffiti SS on a war memorial.
And there is an important difference between condemning something and outlawing it.