The man in charge of setting up the NHS medical records database has admitted that "you cannot stop the wicked doing wicked things" with information.
Checks on data-sharing must be "robust", MPs heard
Richard Jeavons, director of IT implementation at the Department of Health, said there were instances where staff "abuse their privileges".
These had to be "pursued", he told the Commons home affairs committee.
The plan to put 50 million patients' records on the database is part of a £12bn NHS IT overhaul.
The scheme has raised concerns over cost and the security of information.
A poll for the Guardian suggests that 59% of GPs in England are unwilling to upload any record onto the database without the patient's specific consent
Three quarters of more than 1,000 doctors questioned believed medical details would become less secure when they are put on a database that will eventually be used by the NHS and social services.
Mr Jeavons, who was appointed in May, said the Department of Health did not itself hold many people's personal records but added that it provided guidance to NHS trusts on how to handle data.
At a committee hearing, Labour MP Margaret Moran said to him: "Even if we get the technology right, the problem is abuse by people or misuse of data.
"How confident are you that there won't be problems over data and privacy?"
Mr Jeavons replied: "You cannot stop the wicked doing wicked things with information and patient data...
"Of course, we have examples where staff do abuse their privileges and have to be pursued through disciplinary procedures."
He added that the government had to "make sure" that people who abused the system knew they were "going to get caught".
The NHS scheme is intended to "modernise" the service.
By 2014, 30,000 GPs in England will be linked up to nearly 300 hospitals giving the NHS a "21st century" computer network.
It involves an online booking system, Choose and Book, a centralised medical records system, e-prescriptions and fast computer network links between NHS organisations.
It is said to be the most ambitious computer project in the world and represents the largest single investment in IT in the UK.
Opponents say it is too expensive and will compromise the confidentiality of records.
The home affairs committee is looking at whether the UK has become a "surveillance society".
In its hearing, it senior civil servants working in the education, transport and justice fields were also questioned.
The MPs were told different departments could not share information without legal guidelines being followed and rights of access clarified.
Clare Moriarty, constitution director at the Ministry of Justice, said efforts to make data protection as "robust" as possible were essential.
Questioned as to whether information had sometimes gone between departments unofficially, she replied: "I'm not aware of any department sharing data by stealth."
Government chief information officer John Suffolk told the MPs that setting up a nationwide database going across Whitehall departments and other government agencies would create more problems.
He said: "When you work at a national scale, to continue to put more eggs in a single basket is a foolhardy approach."
Mr Suffolk added: "The more and more you put it into a large database, with more and more people having access, it becomes more complex...
"If we can avoid setting up large-scale citizens' databases, that would be a wise thing to do."
The Information commissioner last year warned the UK risked "sleep-walking into a surveillance society".
The committee's inquiry will include the impact of identity cards, the expansion of the DNA database and the rise in the use of CCTV cameras.