Mr Pollard made the offer during a private press briefing almost two weeks ago, but this is the first time he has made it official to the SFO.
One of Mr Pollard's earlier fears was that any information given by Mr Leeson would be passed on to the Singapore authorities, with whom he is fighting an extradition application. It is understood the SFO views Mr Pollard's assurances as the removal of a "major obstacle".
Mr Pollard started a dialogue with the UK prosecuting authority in early June in the hope of eventually winning his client's extradition to the UK.
Next month, Mr Pollard is due to present written arguments to the German courts telling why he opposes an extradition application from Singapore.
SFO sources emphasised that their stance of whether to apply for Mr Leeson's extradition would not necessarily change as a result of an interview. The SFO has said in the past that it does not have sufficient evidence to warrant an extradition application for Mr Leeson.
Earlier this month, Mr Pollard indicated that his client would be willing to plead guilty to at least four charges of false accounting and one other unspecified charge if he were brought back to stand trial in the UK rather than Singapore.
The SFO's change of heart - it had previously indicated to Mr Pollard that it considered an interview of only limited value - comes as members of Parliament's Treasury and Civil Service Committee hinted strongly that they are likely to reopen inquiries into the Barings debacle in the autumn.
"None of us seriously thinks that the Bank of England's report is the last word on the subject," says Quentin Davies, Conservative MP for Stamford and Spalding.
"The Bank's report had no input from Mr Leeson or the Singapore authorities. We are very likely to conduct a full inquiry of our own".
Two Labour MPs on the committee, Mike O'Brien and Diane Abbott, said they were disturbed by what they had heard from the Bank of England Governor, Eddie George.
Mr O'Brien said he thought the Treasury Committee would also be keen to interview Chris-topher Thompson, the former senior manager responsible for merchant banks at the Bank of England, and Carol Sergeant, his immediate boss.
Mr Thompson resigned days before the publication of the report when it became clear that he would be criticised for giving Barings an exemption from limits on the funding of trading in Osaka and Singapore in 1993. He appears to have been well regarded by other merchant banks that dealt with him.
"We want to be convinced that Mr Thompson is not a scapegoat," says Mr O'Brien. "We would be interested in hearing from him," he added.
Diane Abbott, MP for Hackney North and Stoke Newington, said she was "deeply unimpressed" by the Bank of England's performance before the select committee last week. "I think the Singapore authorities might be keen to give us some evidence," she said.
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