Several laptops 'missing' from NHS North Central London
Several non-encrypted laptops have gone missing, and one has been reported stolen, from NHS North Central London.
An inquiry into the missing laptops, including one reported to police on 10 June, has begun. The health authority said all were password protected.
The laptops contain thousands of records. Since 2010 in London, more than 2,600 patient records have been lost in 65 reported incidents.
The Department of Health said trusts must ensure laptops are encrypted.
NHS North Central London covers five London boroughs - Barnet, Camden, Enfield, Haringey and Islington.
It said: "One of the machines was used for analysing health needs requiring access to elements of unnamed patient data.
"All the laptops were password protected and our policy is to manually delete the data from laptops after the records have been processed.
"NHS North Central London operates under strict data protection guidance and is taking the matter extremely seriously."
Helena Kania, from patient group Haringey link, said: "We have a problem in not knowing what has been lost.
"There are obviously problems in the security at the NHS level dealing with patient records."
NHS London records show that between April 2010 and March 2011 more than 2,600 patient records were lost in 65 incidents.
These included information about a serious case review under the London Safeguarding Children procedures being released on a NHS trust website by mistake.
Another hospital revealed the HIV status of a patient to a GP against their wishes.
Following the latest loss of laptops, a Department of Health spokesperson said: "All NHS organisations are expected to ensure that laptops are encrypted, are legally required to comply with Data Protection legislation and are expected to take data loss extremely seriously, be open about incidents and about the action taken as a result.
"Local NHS organisations are responsible for implementing these data handling processes, including which staff need to have access to health records, and for compliance with Information Governance standards."
An Information Commissioner's Office spokesperson said: "Any allegation that sensitive personal information has been compromised is concerning and we will now make inquiries to establish the full facts of this alleged data breach."