"The Swiss messenger service Threema wants to stay in the UK despite the proposed Online Safety Bill. Other messenger services had already announced that they would leave the country as soon as the bill is signed off by Parliament. If the law comes into force, all communications from all providers - whether encrypted or unencrypted - could be viewed if there are corresponding search warrants. In the case of encrypted messages, providers must have some sort of master key for each conversation.
However, Threema does not want to participate in this, as first reported by the portal Netzpolitik. "The current draft laws of the Online Safety Bill and chat control provide for modifications to all affected apps. We are not prepared to include such interfaces for foreign authorities. Not least because this would make us liable to prosecution in Switzerland," the service told heise online. Moreover, Threema is open source and the official builds are reproducible. It is "out of the question to cut back on security and data protection or even actively support warrantless mass surveillance."
Translated from this german article:
https://heise.de/-7531672
