There cannot be a "free" market in general but not in drugs, prostitution or pornography. That is why there must not be a "free" market in general. The State has not only the right, but the duty, to ensure that there is not.
For example, it has not only the right, but the duty, to require that advancing technology be utilised in order to protect society at large from the effects of Internet pornography, which is in no sense a private matter, but has catastrophic consequences in fields such as law and order, health, the education of the young girls now being sexually assaulted by their male peers on something approaching an epidemic scale, and so on.
Forget allowing people to contact their Internet Service Providers in order to have these filters removed from their computers. It should be illegal to remove them, just as it should be legally required to fit them.
Ed Miliband, over to you.