It’s not so much a matter of whether the service would work or not but whether the corporate directors would be exposed to criminal liability for continuing to provide such services without OFCOM being able to “understand” the encrypted messages: see 99(4) of the Bill
Signal and WhatsApp have also said they’d likely leave the UK market if this bill is passed as it currently is.
Signal should still work there if people want to use it, and they don’t block it with a Great British Firewall.
Hadrian’s firewall
It’s not so much a matter of whether the service would work or not but whether the corporate directors would be exposed to criminal liability for continuing to provide such services without OFCOM being able to “understand” the encrypted messages: see 99(4) of the Bill
https://bills.parliament.uk/bills/3137