People on the other end of encrypted conversations outside of the UK would also be surveilled.
More broadly, any backdoor built into any app can and will be exploited by bad actors. Theres no "safe" way to break end to end encryption for just the " good guys".
It will absolutely erode encryption in my country. Our government seems to operate on the following logic:
1. We want to be a developed country.
2. X is a developed country.
3. X does Y.
4. Therefore, we must also do Y.
We have our own GDPR. I've seen judges citing european laws in decisions. Watching other countries pass laws like this one is like getting a glimpse into the future.
I guess then it would be your government eroding encryption in your country. To take it your way, every law passed everywhere has an effect on anything, which is so indirect it starts to become meaningless.
The UK has been getting less relevant for years. It's why tech companies are telling it to stick its laws without concern about losing that market. So its position on encryption is becoming less relevant too. But sure it's erosion and that sucks.
Seems like they'll only be stuck with their own police state friendly system.