Politicians and civil servants will be the biggest losers without unbreakable encryption
Look up the definition of Chekist in Wikipedia. A chekist is a person who supports their country's intelligence agencies and police being able to surveil their fellow citizens.
A Chekist regime is a regime like the old USSR and Putin's Russian Federation where members of the security agencies and police know so much about politicians, business people and academics that they legally have total control via superior knowledge and total control illegally by an unlimited ability to blackmail anyone.
Now with the internet intelligence agencies and police will know so much about people, will have so much dirt from what people posted during their student days, that people posted as adults years ago concerning now lost causes,
Sure, members of parliament, Home Office and MOD officials will grant themselves supposed immunity and exclusions from spying. But the spying will have already been done during their college years, during their early working years, during the recreational time.
No laws will be passed, no plans will be laid, no discussions will occur within political parties or within government offices that would make members of the intelligence agencies or the police unhappy.
Like with Chekist Russia, a Chekist UK, the government, industry and academic of a Chekist USA will be run by, and for the benefit of, alumni of our own security services and police.