PricewaterhouseCoopers chairman Kieran Poynter is half way through his initial interviews with HM Revenue & Customs staff into the loss of 25 million individuals' details and his full findings will only be made in the first half of 2008, he said today.

Poynter said 'good progress' was being made in interviewing those potentially involved in the data loss, and a forensic review of email correspondence was being undertaken.

However chancellor Alistair Darling does not expect the review to be completed until the first half of 2008.

Poynter added that he had been sent 'numerous copies of potentially relevant emails' but they may not represent the whole picture.

The review has been slowed up as interviewees have chosen not to have their interviews recorded, instead having detailed manuscripts noted down.

Interviews with NAO staff will take place until further discussions take place with HMRC staff.