Police cameras that record motorists' movements must be more tightly regulated, Home Secretary Theresa May has ordered.

The 4,000-strong automatic number plate recognition (ANPR) network logs more than 10 million vehicles every day.

The government is to look at limiting access to the database of 7.6 billion images, details of number plates and the date, time and place of capture.

Privacy campaigners said restrictions on the ANPR network were long overdue.

My philosophy is that if you are not doing anything wrong, then you have nothing to fear.

The idea that an individual can live in a surveillance society with nothing to fear so long as they have nothing to hide may, on the face of it, appear attractive. For those of us who think of ourselves as 'honest' - we pay our taxes, don't commit murders and are loyal to our partners - why indeed should we fear surveillance? "Nothing to hide, nothing to fear" (NTHNTF) is a myth that is built on certain false assumptions, and these assumptions are never questioned when it is wheeled out as an argument to support whatever draconian surveillance measure is being pushed out in the face of citizen opposition (commercial organisations rarely try such an approach, since it dooms them to failure from the very beginning). These assumptions include:

Continuity: When a large data gathering exercise is started, the lifespan of the system will almost always be greater than that of its instigators. The most benign and caring government, authority or private company is inevitably subject to a change of management, and if the new executive does not share their moral stance, then data can be reused for very dangerous purposes. Those who provided data believing they had nothing to fear may find that data is misused in the future.

Context: Those who use the NTHNTF argument most commonly use it in the context of government collecting information about individuals. In the information age, the idea of a single entity holding that information does not hold true. The massive pressures to share information within and beyond government mean that information is constantly on the move. Sooner or later, information held by the government will be shared across the government and with the private sector.

Control: Whether through a sharing agreement, aggregation of databases or simply leaving a memory stick in a pub car park, information is always shared sooner or later. Information security professionals always assume a system to be insecure, and plan for when - not if - data is lost or corrupted.

Consistency: The most important issue is that of consistent use of accurate information across all authorities and all individuals.

I have no problem with it for road use such as for stolen cars, unlicenced cars and drivers with arrest warrants etc. I don't think the images should stored for any length of time other than if they were flagged for any of the above reasons.