Alarmed by the loss of his details on a government CD, David Bond decided to find out just how often private information leaks into the public realm

AS IS standard for every good horror movie set-up, David and Katie Bond seem to have a lovely life. They own a large house; they're touchingly and openly in love. David makes films and Katie is pregnant with their second child. They have discussions about which private nursery to send their daughter to, he uses his BlackBerry incessantly and his Amazon purchase history is roughly the size of a telephone directory.

The Bonds' daughter, Ivy, was one of the 25 million children whose details – address, date of birth, records and parents' bank account information – were on two CDs lost during that embarrassingly public period in 2007 when government bodies and civil servants seemed to be leaving sensitive information lying around – in trains, in the backs of taxis – every couple of weeks or so.

"They just didn't know where that information had gone," says David, as we discuss the upcoming release of Erasing David, a documentary taking an unflinching look at the network of surveillance culture and data profiling in the UK. "They couldn't say. And I just couldn't stop thinking about it."

This incident seems to have triggered something primal in David, a protective, paternal instinct that manifested itself in an increasing obsession with how much information the state had on him. He opens the film by telling us UK is now the third most intrusive surveillance state in the world, topped only by Russia and China, a statement that might sound like the rantings of every paranoid libertarian blogger, were it not for the heavyweight political roster of talking heads – Helena Kennedy, David Davis, MP, even former home secretary David Blunkett – who appear in the film backing it up.

David decided to test that out. He hired a private detective agency, Cerberus, to track him down in 30 days, given only his name and a photograph to start out with, left home and headed out across the country. By the end of the opening credit sequence, the agency has already located his address and mobile phone number, just by using information David himself had at some point allowed to be freely available on the internet.

It's important to note that David isn't a libertarian crusader scoring points off the state. He's equally concerned with the amount of information we're ceding, voluntarily, to companies.

In one sequence that would be amusing if it didn't chill the blood quite so much, he applies for 80 Subject Access Requests from government agencies and private companies, to find out what sort of information they have on file about him. We find out the size of his Amazon customer profile and that, according to one unnamed company with a call-centre system, he "seemed angry" and "seemed very angry" on two separate occasions in December 2006.

"This is what companies do," he says. "Tesco give you money to stay loyal to them, in exchange for a very detailed buying history. Facebook provide a free service – they can afford to do so because of the value of the information they're harvesting from you."

Cerberus also began to seize on these sort of clues. They wanted to work out the sort of person David was in order to anticipate his moves. That they were able to do that with matter-of-fact ease is one of the most chilling things about the film.

"They'd worked out that I was interested in the political angle, and that I was a fan of George Orwell. I'd actually intended to take a trip up to Jura, where Orwell wrote 1984 – there was a pin in their map there. There were a lot of frightening pins in that map. What they'd done was conduct a successful profile based on the information about me that was available, which is exactly what marketing companies do all the time. I hated the fact that they'd got it so right."

Before he leaves, we watch Katie raising the very reasonable point that, by disappearing for a month, he is saddling her with a huge and unfair amount of extra childcare. When I bring this up with him, he takes very sweet pains to assure me he's made that up to Katie now. Where I wanted to talk about the political implications of this scene, that we have all become, to some extent, bound by our responsibilities to live docile within a surveillance culture, David is entirely concerned with the personal aspect.

"Until I received that letter, I hadn't been particularly concerned with any of this. At that time, my co-producer was about to have a kid as well and, as young fathers, we wanted to know what on earth was happening here. We wanted to make a film for people like us."

Undergoing this experience has turned him into an activist for privacy rights, so Erasing David's release in the run-up to a General Election doesn't feel entirely coincidental. But David is insistent that his main purpose is to provide a service to other people and families.

"I'm not massively optimistic about politicians coming in and repealing any of this legislation, demanding that databases be scrapped. What I think is most important is that people begin to ask why this is happening: that we stop handing out our birthdates or mothers' maiden names willy-nilly, and realise the value of our own information."

• Erasing David screens at the Cameo, Edinburgh, and the Belmont Cinema, Aberdeen, on 29 April. A live debate with Will Self and David Davis, MP, will be screened after the film. Erasing David is also broadcast on More 4 at 10pm on 4 May. For more information on the issues raised in the film, see erasingdavid.com