With the ever-encroaching spread of our surveillance society, there is an old maxim that if you have nothing to hide, you’ve nothing to fear.

One man who would strongly dispute that is David Bond, the director and star of new documentary Erasing David, which is being premiered in the UK by the Picturehouse cinema chain on Thursday.

Inspired by the loss of his four-month- old child Ivy’s details by the Child Benefit Authority only days after he had registered her, David decided to make a film looking into the information that is held by government and corporate databases about UK citizens.

And as part of the film he disappeared for a month, to see how long it took two private investigators from the firm Cerberus to track him down.

All they were allowed to use was the information they could glean legally from the internet and publicly-accessible databases.

What he uncovered shocked him.

“We are living in the worst surveillance society after Russia and China,” he says. “Countries like the US look at Britain as a nightmare, where it has all gone wrong.

“In London, where I live, there has been the growth of CCTV, Oyster cards which can follow where you travel on trains and buses, the congestion charge with its number plate recognition technology, and the rise of face recognition cameras.

“I wanted to make a film for people who don’t normally worry about these things.”

After an initial plan to ask somebody else to disappear, David elected to vanish himself, his only connection with his family being a pay-as-you-go phone to keep in touch with his pregnant wife.

The date planned for the disappearance was January 10, 2009.

“In the days leading up to then I was really careful with the way I used my credit cards, drew money from the bank and used my mobile phone,” says David.

“I didn’t want to stay in one place for too long. I had spoken to one of the private investigators briefly on the phone, but the way they were hired was through my creative partner Ashley Jones [the film’s producer].

“All they had was my name and a photograph. They weren’t allowed to break the law, although I had to sign a document saying that if they invaded my privacy in any way I wouldn’t be allowed to sue them.

“Everything they did, they did through avenues that are permissible for anybody to access.”

At the end of the experiment, David was led into the pair’s control room, and was horrified to see what they had uncovered.

“There was a giant wall of the room which was covered with my data, with a massive picture of me in the middle,” he says.

“It was all carefully organised in bulldog clips, with information about my education, my family, my wife, my bank details. It was like a nightmare.

“The Government and corporations are hungry for this stuff. The Government want to use it to control us, to make us behave in ways they think are right.

“The corporations want to sell to us. What is freaky is how much stuff is out there, which people have put out for the world to see. I don’t use Facebook any more, but they still managed to dig out the list of my friends from it.”

A big part of the private investigators’ work was the way they were able to build profiles from seemingly disparate pieces of information.

“They were able to get enough about my shopping habits from databases generated from businesses such as Tesco and Amazon so they could work out what I liked and what I didn’t like,” says David.

“They got my birthplace, date of birth and address in no time at all. The way they describe it is they can find out a colossal amount of information very quickly, which they can then piece together to find out not only what this person has done in the past, but they can begin to produce what they might do in the future.

“In my case they worked out very quickly I was a film-maker, unsurprisingly, as they were being filmed at the time. From then it was only a short step to work out which places I might be hiding. They knew I had an interest in George Orwell, so they had pins in the map for the island where he wrote 1984, and also the location where the Magna Carta was signed – places where I might go to make a film.

“There is nothing magic. A lot of what they do is about strategy. It becomes spooky when they put it all together into a profile.

“My aim was to be unpredictable. I could have just dug a hole and lived in it for a month, but I didn’t want to do that – it’s no sort of life and it wasn’t what I was trying to prove. It was more about whether it is possible to have any semblance of a private life.”

David feels the results were deeply unsettling.

“I’m a relatively ordinary guy, I’ve not been in trouble with the police for example, but I was shaken up by how much is out there,” he says.

“The film is also asking how we have ended up in this situation. We are a country that celebrates personal freedom, which is supposed to protect the individual from the state and big business, but now this stuff is routinely collected and stored.

“It has changed my life. Now when people ask me for data I always ask why they want it. I’m really determined that my kids should be able to avoid this.”

For more information about how to monitor the information given to databases about children you can visit the film’s website www.erasingdavid.com where Terri Dowty at Action On Rights For Children has provided a privacy guide for parents.

Anyone who thinks these issues won’t affect them should hear the story of Emma Budd, whose case is examined in the film. She wanted a job looking after vulnerable children, inspired by the fact her brother is disabled. But when she went through the Criminal Records Bureau check, her data was mixed up with a shoplifter of the same name.

After a year she managed to clear her name – only for the same thing to happen again when she reapplied.

“If you have got nothing to hide, then you’re exactly the sort of person who has something to worry about,” says David. “If you are a criminal you are off the databases. It’s the ordinary people who get mixed up with others and who have their details stolen. It is much more common now, because it is much easier to do.”

* Starts 8.30pm, tickets £7.50. Call 0871 704 2056.

* The screening is followed by a satellite question and answer session from Brixton, hosted by Will Self with David, David Davis, the MP who resigned his parliamentary seat over the erosion of civil liberties in the UK, Phil Booth of NO2ID, Shami Chakrabarti, director of Liberty, and celebrated composer Michael Nyman who is also a privacy campaigner and provided the music for the film.