The head of the government's accounting watchdog claimed that efficiency savings led to the taxman's decision to send sensitive data on child benefit claimants.

Edward Leigh, Public Accounts Committee chairman, said that providing the child benefit information to the National Audit Office stripped of sensitive data was found to be too expensive a process, and would involve payments to its IT contractor, reported the FT.

Chancellor Alistair Darling yesterday insisted that the merger of the Inland Revenue and Customs & Excise, plus ensuing efficiency drive, was nothing to do with the loss of the child benefit data.

The FT also reported that NAO boss Sir John Bourn said senior managers at HMRC were also aware that the data would not be desensitised.

It had earlier been claimed that a junior member of HMRC staff had unilaterally put together the data onto two discs and sent it via internal post to the NAO.

Further reading:

Hartnett takes top job at HMRC

HMRC's data loss: what the papers say

Tabloids lay into government over HMRC data loss