You probably have not heard of Mr Thomas, a mild, middle-aged man with the manner of a slightly baffled bureaucrat. But he is an unlikely freedom fighter in a battle that is becoming more fraught: the battle for information. On you.

As the Information Commissioner he is the man standing between you and a bad credit rating, between you and an inaccurate police record blacklisting you for life, between you and the Government hiding crucial decisions about your future. And now, between you and the companies, such as banks, playing fast and loose with your confidential financial details.

“We’re waking up in a surveillance society,” he said. “And when you start to see how many well-intentioned, apparently beneficial schemes are in place to monitor people’s activities and movements, I think that does raise concerns. It can stigmatise people. I have worries about technology being used to identify classes of people who present some sort of risk to society. And I think there are real anxieties about that.

“A company can send you a mailshot and say you’re clearly the type of person who likes this sort of holiday, they can profile you. In the same way, public authorities can profile you,” he said.

“You can manipulate data in a way now which builds up a very full picture, which may not be the right one. It may be an inaccurate picture. To treat somebody as a suspect when there’s no more than a potential for fraud is a serious matter.”

Scary stuff; and he got scarier.

“I would question whether there’s a greater case for convergence between police files and tax files and between bank records and health records,” he said. “There’s a trend towards greater convergence and it can classify people in ways which may be wrong and artificial. But there is also the risk of mistakes. There are risks the information is going to be mishandled.”

The threat is out there, but it’s all a little vague — which, given that Mr Thomas is dealing with theoretical dangers, may be understandable. His worst fear is of all these statesponsored monitoring systems linking up to one electronic Big Brother.

Take the children’s register: within a couple of years the Government aims to record electronically basic details about every child in England, including their address, school and doctor. Any professional who has concerns about a child will be able to add a red flag to their file, so that if others involved are also worried they can get in touch and share information. Is this an essential child-protection measure or a sinister bar-coding of childhood?

“I’m not persuaded that it’s necessary to set up an index of every child in the country where the rationale is to do with ensuring the social, educational, general health, wellbeing and thriving of all children,” he said.

“Now, if there are going to be flags of concern, let’s be precise — what do we mean by a flag of concern? If a child is being abused or there are very strong allegations of abuse, that’s clearly a concern. Is it a concern that the child is not thriving at French GCSE? We have to define this more precisely. And I think it’s part of our job to force those who are bringing forward these schemes to be as clear and open as possible on what they’re doing, why they’re doing it.”

So Mr Thomas tries to police this line between what should be your own affair and what it is necessary for the State to know. His job tugs him in both directions, upholding the Data Protection Act on the one hand, and forcing openness through the Freedom of Information Act on the other.

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