BDO Stoy Hayward is set to be named as the valuer of Northern Rock, Accountancy Age understands.

The mid-tier firm has got the deal to reach a valuation for the mortgage lender, one of the most high-profile victims of the credit crunch.

BDO will be required to say how much the lender would have been worth if it had not been propped up by the Bank of England, in an attempt to resolve issues of compensation for shareholders.

The choice of BDO may come as a surprise. A Big Four firm would normally have been expected to take up such a role, so it may be seen as a big coup for BDO.

There were suggestions that the larger firms were not keen to take on the role given the potential litigation that would surround taking on the job. Insiders have insisted, however, that there was more interest than press reports had suggested.

An announcement from the Treasury confirming the appointment is expected later today.

A spokeswoman for BDO said the firm could not comment on press speculation. The Treasury has not commented as yet.