NHS medical records database A £12 billion NHS system is being created to hold the medical records of 50m patients. Some GPs and campaigners fear it is insecure. In one trial a doctor said he had been able to access both Cherie Blair’s and John Prescott’s NHS files from his practice’s computer.

DNA database The largest in the world, it holds details of 4.25m people and is growing at a rate of 30,000 a month. Everybody arrested by police is added, including an estimated 1m people who were not eventually convicted. It includes DNA from 900,000 children.

Police records The police national computer in Hendon, north London, holds 96m pieces of information, including criminal records and details of arrests. It is accessible 24 hours a day to police, court and Criminal Records Bureau staff.

DVLA database Holds the names, addresses, driving licence and vehicle details of 42m drivers. The database attracted controversy after it emerged that the DVLA had made millions selling details to private car park and wheel-clamping operators.

Q&A: how can I protect myself?

Advice for anyone who fears their personal data may be misused by fraudsters after Britain's worst ever security breach

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Background

• Police step in as other CDs have gone astray

• Moment’s blunder puts half the country at risk

• Data watchdog seeks dawn-raid powers

• New data law 'urgently needed'

HMRC Her Majesty’s Revenue & Customs holds the names and addresses of 6m people who make tax credit claims and also stores the names, addresses and National Insurance and salary details of the 30.5m people who pay income tax. And, of course, the details of all those who receive child benefit.

Benefits computer Includes full income and personal details of anybody in receipt of benefits, including 11.5m with state pensions, 2.65m incapacity benefit claimants and 4m who claim either pension credit or income support.

Passport database Holds the names, dates of birth, passport and immigration details of 45m UK citizens. Private firms can pay to check a person opening a bank account.

COMING SOON:

ContactPoint This will hold the name, address, gender and date of birth of every child in Britain and can also include information on sexual history, mental health and substance abuse. It will be accessible by NHS staff or by social services.

E-borders A £1.2 billion scheme to monitor passengers on entry to and exit from the UK. Data will include credit card details, holiday contact numbers, travel plans and e-mail addresses.

National Identity Register The £5.6 billion identity card project, set to be introduced in 2009, will hold your name, address and biometric information along with numbers for National Insurance, passport, driving licence and any other “designated document”.

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