I don't think politicians set out to do this but it's been around in some form or other in Whitehall for so long that there's no real responsibility anywhere and it was low priority enough that noone ever thought to properly kill it.
It's very British in that sense.
That this will lead to a significant amount of crime is simply assumed, and not from any basis in reality. They also misuse statistics to try and make issues look larger than they are, which does a disservice when these are actually really serious issues. Like with CSAM, they always talk about so many millions of reports, without mentioning that reports are only suspected content, and the vast majority turn out not to actually be illegal (something like 70-80% of reports are discarded by law enforcement in the first pass - but it's understandable that platforms have to be extremely conservative and report anything that even looks a little like it could possibly be CSAM). Then there are massive amounts of duplication and things like that. But it is a serious issue, so it does my head in that they misuse the 'big, impressive reports number' when they know only a fraction lead to investigations, because that just gives critics a basis to show that they're massively exaggerating which could lead people to minimise the issues.
Of course, at the end of the day, you can't surveil your way to safety and these problems are best solved at the source. But that would require things like fighting poverty (oh no, welfare spending!) and deploying large numbers of social workers to help support people in marginalised communities.
As we progress with climate change and climate disaster, it’s clear that eco terrorism is going to be increasing. This has been especially highlighted in UK.
I put it in quotes because honestly it’s just fighting for survival at this point, but the ones in charge have decided to add the word terror to make it scarier.
Personally, I don't think this is a particularly legitimate concern (and by extension, not one which I would assume the government has), since the whole point of revolutions is that they don't need to be planned; they are a groundswell of popular opinion turned violent. Even if encrypted group chats were necessary for ecological campaigning groups, I don't believe they are popular enough among the British public or violent enough to make even a minor dent in the Britain establishment.
though to your point, that form’s more of an economic weapon than it is terror.
The basic premise is that online platforms like Facebook and X will have more legal responsibility and requirements to follow particular UK law and guidance on content that their platforms host.
This is very popular with the press and enjoys widespread public support in polling. All major political parties support it.
The encryption and scanning aspects of it are just one part of the bill.