When the woman who exposed the MPs expenses scandal says she’s uncovered the next big public outrage, it’s impossible not to take notice.

Heather Brooke explains to the Huffington Post UK why data dealing is even bigger than phone hacking and the reasons she lost faith in WikiLeaks founder Julian Assange.

Somewhere in an upmarket central London restaurant over lunch the negotiations started at £100,000. Heather Brooke witnessed the document with the names, addresses and telephone numbers of every voter in Britain go on sale.

The investigative journalist and campaigner says the attempt to sell the electoral register was just one example of data dealing – the burgeoning trade in personal information that could affect any citizen with an online profile.

“I don’t think people have any idea that this goes on all the time. There are corporate private investigators, companies doing very forensic background checks on people. They buy data, they get their own data … They don’t want their industry publicised”, she says.

The phone hacking scandal exposed how the private lives of celebrities and the bereaved had been targeted by journalists. But according to Brooke, her latest investigation will show now everyone’s details are up for grabs, and not by reporters, but by companies.

“Phone hacking, that’s just touching the surface of that whole industry in personal information which is vast, huge, it’s massive,” she says.

Two years ago a wave of public outrage forced the Home Office to abandon plans to set up a so-called ‘Big Brother database’ to collect information about every website you visited, phone call you made and email you sent. In the new information era exposed by Brooke in her forthcoming book, that doesn’t matter, companies can just piece together that information about you anyway.

And she says they can use instant message conversations, pictures, the texts you receive and your Facebook status.

Brooke warns corporations and governments are a “customer” for information, and they want it for a reason: “It’s trying to predict the behaviour of different people and it’s making decisions about who it thinks are going to be trouble makers, not based on what you’ve actually done but based on what they think you’re going to do in the future.”

She doesn’t subscribe to the ‘if you have nothing to hide, you have nothing to worry about’ philosophy: “If you believe the promise that an authoritarian state makes that if it has enough knowledge on every citizen it will keep people safe. I think that’s a false promise. It doesn’t actually happen. If that was the case then East Germany would be a really incredible place to live and in fact it wasn’t, it was really horrible, most of these places were really horrible.”

And as the amount of data about people increases – google searches, text messages, emails, chat logs, purchases – so does the value of what it says about you. The websites you like to go to, the products you like to buy, and what exactly you might get up to in your spare time. And with more data comes opportunity for democracy - or suppression.

Brooke explores this in new book, ‘The Revolution Will Be Digitisied’, part crash course in information held by the government and corporations, and part thriller, focusing on the drama surrounding WikiLeaks’ attempts to expose US diplomatic cables and the gradual implosion of the organisation.

For Brooke it comes down to the dangers when there is a concentration of power – either with WikiLeaks or in government. The investigative journalist and campaigner made it clear she was not afraid to take on vested interests during her five year campaign to expose MPs’ expenses. And she says pockets of public outrage when it emerges that iPhones keep track of everywhere you go aren’t enough.

She’s scathing about David Cameron’s response to the riots in Britain, proposing to monitor social networks like BBM and Twitter.

“I think it’s interesting the political reaction is ‘we have to start surveying all the social networks’. That’s the instant reaction. That’s what I mean about how the revolution will be digitised because it totally shakes up power structures, it does put power in the hands of people, including the proletariat, chavs, whatever you want to call them. They’re on social networks now, they can organise, they can communicate. And people that are in power, in the more elitist bastions of power, they find that really frightening. It’s challenging, it’s frightening, they don’t know what to do, their kind of instant reaction is: let’s shut it down.”

For her, governments haven’t “evolved fast enough”: “People are used to getting a lot of information quickly and they’re used to being quite empowered as consumers and they go to governments expecting a similar treatment, they want to find data and they want to influence events quickly and yet they come into this brick wall. The government wants to know everything about them but isn’t willing to share any of that information.”

Julian Assange, of course, plays a part in her quest to free up data. Initially, she’s attracted to him (“He’s the world’s most famous leaker, I’m a freedom of information campaigner so we’ve a lot to talk about”). But he also unsettles her, telling her without fear she can become a “megalomaniac” like him. She says in her book “I couldn’t have felt less comfortable alone in that room with him”, and most strikingly, reveals that he asked her to be his Mary Magdalene and “bathe his feet at the cross”.

Now, Brooke says she would not have been tempted by Assange even if she were not married: “He did strike me as a kind of dangerous person.”

She says it was his domination of the WikiLeaks exposes that left her disillusioned with the founder.

“The values of WikiLeaks have been completely overshadowed by Julian Assange. And he’s trying to conflate the two as one. Which is why a lot of the good people left. The people that I thought were the best people left. It is basically the Julian Assange project now.

“I guess that’s the real disappointment in the book. There was this opportunity in 2010 to really revolutionise the way information was shared, and instead of that cause going forward and being the main thing it was subverted, I felt and I observed by Julian Assange to serve his own personal interest and protect himself from personal problems.”

She says the leaks on Iraq and Afghanistan could have actually changed government policy, if it weren’t for Assange.

“I think they could have had a pretty big effect on America’s view of that war. But … because of the way Julian personalised those stories and made them about him rather than the story itself.”

Suddenly we’re back to the hacking scandal again: “That’s all Nick Davies, right? Does Nick Davies give a press conference himself about Nick Davies? No he doesn’t, he lets the story speak for itself.

“That’s what Julian needs to take on board. If you’re really serious about wanting to change society you have to pull back off the story, let the facts speak for themselves and stop trying to micromanage the way the public interprets it.”

It’s clear that she’s angry at him, for subverting a cause – the campaign to free up data to create enlightened citizens – into a campaign about him.

“He took this cause and took an amazing opportunity that he had this incredibly powerful set of leaks and used it for his own self-aggrandisation and to save his own skin. In the sense that, initially’ when the allegations came in Sweden he wanted to use WikiLeaks donations for his legal defence, for that personal case… I just think that’s unforgivable. If you really believe in a cause let the cause speak for itself. And if you by your personality are damaging that cause, if you really believe in it you step aside.”

Then there’s Bradley Manning, the soldier who stands accused of giving the data to WikiLeaks.

“He sort of remains the unsung hero of this whole story. This is another reason why I’m so angry about the way Julian Assange this whole movement, this campaign. And that information, if it did come from him, he’s advanced his career off the back off this poor kid who’s sitting in jail. If anybody is responsible for what’s happened, it’s him, who put that into the public domain. We should be thinking about that, rather than Julian.

“It’s difficult to talk about because he hasn’t had his first hearing ... The morality of whoever did it I think it raises a lot of moral questions about what we have a right to know in a democracy.

“Until Bradley Manning comes to trial nobody knows a) if he did it and b) what his ultimate reasons for doing so were.”

So what’s next for Brooke? After her role in two of the biggest scandals of the decade, WikiLeaks and expenses, she says it’s time to stand back.

“I think I’m going to write a novel. I’m just going to drop out. I feel pretty burnt, this was such an intense year. The fact that I started off writing a story which I was really interested in but initially I found it really difficult to sell this book. Nobody got what I was on about.

"They didn’t see it and they just thought ‘oh doesn’t sound like a story’… It was just so exhausting to be working on a story and then it just to kind of take off right before your eyes. And then I got embroiled in it, so then I became a character in my own story. I think I just want a break, just kick back.”