News 

The data includes the address where incidents occurred, phone numbers, patient names and medical details.

Details of 894,629 calls made since February 2006 to an emergency response centre in Paisley were stored on a portable hard drive being transported by courier TNT.

The hard drive was sent on 9 June to MIS Emergency Services in Manchester, which runs the ambulance service's computer system, but did not arrive.

"All

"The information stored on the disk is fully encrypted and it would be extremely difficult to access any names or addresses."

"Despite assurances from the health secretary that the lost disc is fully encrypted and contains no private medical records, this loss of data is of huge concern to many people," says Brian Spector of security firm Workshare.

"The public has a right to know about data breaches as soon as they occur, regardless of whether security procedures have been followed or not."

The incident is the latest loss of confidential data since HM Revenue and Customs lost 25 million child benefit records in the post last October.

An Independent Police Complaints Commission report into the HMRC data loss is due to be published tomorrow.