All but the most witless husbands can smoothly continue with their nefarious habits without troubling the wife. A study last year found that a third of visitors to adult entertainment websites were female.

Cameron is making life unnecessarily difficult for all of us.

If the installation of family-friendly filters in 20 million homes makes it even a tiny bit harder for young children to show each other disturbing images then, politics aside, what is the harm?

We have to actively address this issue – and this filter is a tiny part of that.

“Darling, I’ve given this great thought, and I’d like our house to be listed on the Government’s filth register as 'a bit smutty’ – is that OK?

” Even though most porn is made by consenting adults for consumption by consenting adults and breaks no laws, thanks to Cameron’s Victorian crackdown, we’re all going to be made to feel slightly degenerate.

Back in the real world, the Child Exploitation and Online Protection Centre (CEOP) says that serious users of abusive images will still obtain this material through peer-to-peer file sharing.

The centre wants more trained officers to entrap paedophiles online. Presently, the Internet Watch Foundation (tasked with identifying and blacklisting links to child abuse material on peer-to-peer networks, which allow abusers to share material without searching on the open web) has just five staff.

It’s easy to assume that your own ignorance disqualifies you from giving advice, and leave your children to their own devices. I broached the subject with my 11-year-old, who revealed that a friend had tried to show him porn but, said my son airily, “the site was down”.

I wasn’t about to forbid my son to see his friend, but I bristled with helplessness and anger, about what felt horribly like an inevitability.

It’s only reasonable to make allowances that, preferably, don’t involve friends or colleagues.

The real shame is to be stuck in a relationship so brittle that it can’t tolerate a – how can I put this? Is having to opt in or out of a family-friendly filter really a genuine assault on personal freedom?

If this wasn’t such a glib response to this threat against our children it would be terrifying.