There's a reason most of us lock our phones with a passcode. We know they've become a window into our private lives, much more revealing than a rifle through our diaries or bedside drawers. They contain our contacts, banking details, confidential work emails and personal messages - highly valuable in the wrong hands.
So if a stranger approached you in the street and asked to see your browsing history or text messages, you'd naturally recoil. And that's exactly how people responded when Liberty sent Olivia Lee out to do just that. Even Home Office staff couldn't see why she should get to hoover up everybody's communications data.
But under the Investigatory Powers Bill, the latest resurrection of the Snoopers' Charter, we won't get a choice.
The Bill seeks to legalise the disturbing mass surveillance powers exposed by Edward Snowden, and add even more intrusive ones for good measure. It will all but end the ability of ordinary people to correspond in private - even with doctors, lawyers or journalists. And the Government thinks people don't care enough to raise their voices and stop it becoming law.
Telecoms companies are already forced to store the who, where, when and how of every single person's communications - data that can then be accessed by a massive range of public bodies, from the DWP to HMRC, with no robust safeguards. Liberty is currently challenging the legality of that power in court - but the Home Secretary has stuck it in the new Bill anyway.
And she's gone further. The Snoopers' Charter would make the UK the only country in Europe to force internet service providers to store every single citizen's internet connections for a year - that's your web browsing history, smartphone use, online gaming, television streaming, and more. That means your every internet connection would be logged in a huge bank of information guarded by internet providers like TalkTalk, revealing when you're at home, when you're awake and asleep, and your most private online activities, thoughts, feelings, worries and interests - from the banal to the embarrassing. These huge databases would be honeypots for hackers.
Our digital security is under attack in the name of total surveillance. The Government is creating powers to force telecoms operators - defined to include a diverse range of organisations from Gmail, Facebook, Whatsapp and Twitter to offices, businesses and law firms - to remove encryption, and ban them from even telling us they've done so.
So the major debate in the US - Apple fighting the FBI's attempt to force it to hack into a phone due to concerns it could make every device vulnerable - wouldn't even take place in the UK.
In fact, the Bill would hand police and intelligence agencies the power to hack thounsands of our devices.
Not only is this an unprecedented intrusion into the lives of innocent people in a supposedly liberal democracy, but it would open up dangerous back doors to our data for criminals and foreign spies.
The Snoopers' Charter would also allow our intelligence agencies to acquire, retain, access and link "bulk personal datasets". These are massive databases seized, copied or stolen across the public and private sector containing personal information on thousands of ordinary people including biometrics, medical information, political opinions, sexuality, web browsing histories and more: a mind-blowing searchable vat of data on virtually all of us. The Stasi could only have dreamt of it.
The Government hasn't explained how these hugely intrusive powers will make us safer. It hasn't addressed the concerns of tech industry experts, former surveillance chiefs and three cross-party parliamentary committees who ripped the plans apart.
And, despite a growing consensus that mass surveillance actually hinders spies by drowning them in irrelevant data, it has refused to review whether targeted, not total, surveillance might be a better and more effective way.
Liberty was one of the leading voices calling for an overhaul of our surveillance laws. We urgently need a framework that will help our agencies prevent and detect crime, while safeguarding our privacy and security.
The logical way to keep tabs on criminals is through targeted surveillance. The terrorists involved in major attacks of recent years - from 9/11, to 7/7, to Paris - were all known to security services.
But the agencies are already thought to process 50billion communications a day under existing powers - and these proposals will pile even more on their desks - making it increasingly likely they'll miss crucial details, follow false leads and ultimately fail to keep us safe.
The Investigatory Powers Bill proliferates spying for the sake of spying. It legalises the speculative mass surveillance powers being challenged in court by Liberty - and ignores suggestions there could be a better, more effective way.
The Government sees the positive steps we all take to protect our privacy as a threat to be overcome at all costs, while failing to target resources at the real dangers.
If our representatives allow the Investigatory Powers Bill to become law, no passcode in the world will be able to secure our safety and our privacy. Please sign and share Liberty's campaign, and tell your MP to ditch this fatally flawed law and give us the targeted, intelligence-led system that we need and deserve.