An apology offered to teachers whose personal details were lost on a disc that went missing in the post "does not go far enough".

The National Association of Schoolmasters and Union of Women Teachers (Nasuwt) called for compensation to be offered to any teacher who could prove their details had been fraudulently used.

Almost 11,500 teachers' names, addresses and registration numbers were on the encrypted disc which vanished while being couriered to the General Teaching Council's (GTC) Birmingham office.

The GTC wrote to all teachers apologising for the loss and promising that it had strengthened security measures on its records to help prevent the information from being abused.

And a spokeswoman stressed that no financial information, National Insurance numbers or dates of birth were on the disc.

But Nasuwt general secretary Chris Keates said that was no guarantee the details would not be used maliciously.

Ms Keates said: "It is not acceptable for the GTC simply to assert that they believe the risk of fraudulent misuse of data is very remote."

"Hardly any information is required these days to access financial accounts or to support identity theft.

"The name, address, place of work and in some cases signature is more than enough.

"The GTC must be prepared to indemnify any teacher who can demonstrate they have suffered detriment and should write to every one whose details have been lost making this clear.

"The simple apology they have offered does not go far enough."

Ms Keates also said the issue could be made worse because many teachers simply ignore GTC mail, adding that the union would be also be sending out letters.

The disc, which contained details of teachers who had updated their registration information online, was one of two sent by a contractor to the GTC's office in Birmingham using Parcelforce's full tracking system.

It was first spotted missing on September 12, and full search of Parcelforce's vehicles and depots failed to uncover it - though the GTC said "all the evidence" suggested it was still in the courier system.

© Independent Television News Limited 2009. All rights reserved.