You greatly overestimate our legislators. Of course, they may react in the way you described, but I sincerely doubt we're witnessing some great master plan.

UK is literally the only country except for China that pushed to disable Apple E2E encryption country-wide. It doesn't matter how secure Avanced Data Protection is and how trustworthy is Apple. Just think on it.

Also UK had law for years that can land you in prison for not providing decryption keys for data that you supposedly encrypyted. It's not actively used, but it's there.

So nope, there plenty of UK politicians from both parties that will happily push something that will invade your privacy. And really no one who push against it.

I suspect it's more likely that there actually are a handful of politicians and influential people who do think and plan like that, who exploit the fact that most other politicians and influential people are quite ignorant and easy to lead around by their fear.

Indeed, the simplest explanation is that they are hearing from voting constituents that porn and other objectionable content is too easy for kids to get online, and want to be seen as "doing something about it."

Most parents don't want their kids looking at porn. While there are steps they can take to prevent it, they require some technical knowledge and are generally easy to get around. The easy availability of this content is what has changed. You used to have to go to a seedy bookstore, "adult" movie theatre, or video rental business to get it, and they wouldn't let kids in. Also you had to pay for it, and most kids don't have any money.