Opposition politicians have called for the planned national database of NHS patient records to be put on hold while the government assesses data security.
The government's ability to hold data securely has been further questioned by the revelation nine NHS trusts lost the records of 168,000 patients.
Andrew Lansley, shadow health secretary, said the planned national patient database had to now be in doubt.
The Conservatives argue the loss of memory sticks and data CDs by the nine trusts is further evidence of the government's failure to protect personal information.
Mr Lansley called on the Department of Health (DoH-) to show how it plans to protect medical records held on the electronic patient's database.
He added: "For over two years we have argued for data to be held locally, with networking rather than on one central database. The government should accept this would offer us greater protection."
The Liberal Democrats have also called for further spending on the NHS database to be halted pending an independent security review.
Lib Dem health spokesman Norman Lamb said: "The loss of hundreds of thousands of patients records highlights the dangers of centralising patient data.
"If the government is to restore faith in the national database, it must immediately institute a full independent security review with a commitment to publish its conclusions. Until then all further spending on the database should be halted."
With tens of millions of personal data now lost by the government and public bodies, the information commissioner today reprimanded officials for the way they handled data.
Richard Thomas warned a perceived lack of security was putting organisational credibility at risk and undermining public confidence and trust.
Speaking to the BBC, Mr Thomas said: "Right across the piece people here have got to take personal information a great deal more seriously.
"In the last few months people have got a tipping point where they are suddenly taking data protection far more seriously."
Mr Thomas has already spoken to NHS managers over his concerns about the planned Connecting for Health IT programme.
He said managers must be "absolutely certain" they have identified all the risks involved in sharing medical data and that these have been managed.