It is important to bear in mind those who do need to hide their details - the abused wives, (and husbands), stalkers victims, those fleeing from forced marriages, those under police protection etc. Search engines can identify in seconds what it would take weeks to do manually. Allowing all police officers, all civil servants, or all NHS workers access to national databases will allow the rogue employees the ability to track down their victims, it has happened already, and this will make it easier. I would feel more reassured if the only access was after judicial review, rather than the home secretary of the day, who hasn't time to look at all cases thoroughly.
The 'Hunted' programme recently showed how easy it is already to find anyone and track them, I would like to see evidence that the proposed new law actually is needed.
Essentail reading - The Circle by Dave Eggars, it will frighten you! www.amazon.co.uk/Circle-Dave-Eggers/dp/0804172293