BAE Systems has said that it is "concerned" to hear of the data loss, but that it is "a matter for the Serious Fraud Office".
The defence giant also confirmed in a statement that the material was not sent to a current or former employee of the company.
We were concerned to hear of this unfortunate incident but understand it has now been dealt with by the relevant authorities. Ultimately, this is a matter for the SFO and as far as BAE Systems is concernedit is now closed.
The SFO has stumbled from shambles to shambles, with the Attorney General completely failing to get a grip. It looks as if this blunder would never even have been revealed if he had not been compelled by Labour to divulge the information to Parliament. His account of what has happened raises more questions than it answers. How did this happen? What category of documents are we talking about here? Who received them by mistake? How much of the evidence has been destroyed? What is the Government doing to ensure that this never happens again?
Incompetence like this threatens to have an impact on the reputation of the UK and its relations overseas. People will be wondering how many other skeletons there are in the SFO cupboard that the Attorney General is aware of but is declining to make public. The Government needs to get a grip, get to the bottom of this mess and come clean about exactly what went wrong and how.
Serious Fraud Office appear to admit up to 640 pages & other data is or could be still lost - http://t.co/Z7q7sbLN2I
The statement said that of the 32,000 pages of documents, 98 percent had already been recovered and that "efforts continue to recover all the remaining material that has not already been destroyed by the recipient".
A statement from the Serious Fraud Office (SFO) relating to the accidental transfer of thousands of pages of evidence to the wrong person said:
The SFO has a duty to return material to those who supplied it, upon request, after the close of an investigation. In this instance the party requesting the return was sent additional material which had in fact been obtained from other sources.
The data constituted 3 per cent of the total data in the case. It consists of 32,000 document pages, 81 audio tapes and electronic media. Of this, 98 per cent of the material has been recovered and efforts continue to recover all the remaining material that has not already been destroyed by the recipient. No material relating to national security was included in the data.