By Anita Coulson
Nigeria's attorney-general is stalling efforts to recover millions of dollars looted by former Nigerian officials, sources have told the BBC.
Mr Aondoakaa has refused to comment to the BBC
Michael Aondoakaa has complained of procedural problems in a UK request for help in the case of a former governor, accused of diverting public funds.
James Ibori's $35m assets have been frozen by a British court and the UK wants Nigerian help in the case.
British officials insist that their request was made in the normal way.
Sources in both London and Abuja have told the BBC News website that there is widespread concern that the attorney-general's insistence that everything be done by the book is a delaying tactic.
Mr Aondoakaa was named attorney-general in July, after President Umaru Yar'Adua took office six months ago, promising to tackle corruption.
James Ibori is one of several former Nigerian officials under investigation by British police - at Nigeria's request - for alleged money-laundering of looted public funds.
James Ibori is one of 30 former governors under investigation
In the Ibori case, as in previous ones, the Nigerians were asked to supply evidence that the disputed assets could not have been obtained by honest means.
This exchange of information, under the Mutual Legal Assistance agreement between the two countries, is required to satisfy a British court that the assets are the proceeds of crime and can be repatriated.
As state governor, Mr Ibori's annual salary was less than $25,000 a year, yet he was able to transfer millions of dollars to UK bank accounts with which he bought expensive properties and cars.
Yet an official letter to the office of the Nigerian attorney-general (AGF) from Britain's Crown Prosecution Service (CPS) failed to result in the customary sharing of evidence.
Instead, the letter was published in the Nigerian media, while Mr Aondoakaa suggested the British had failed to use the appropriate channels.
A letter from Britain's Director of Public Prosecutions Ken MacDonald warned Mr Aondoakaa that it was not just the Ibori case being endangered by the lack of co-operation.
"The difficulty and lack of progress in obtaining hard evidence from Nigeria is causing major difficulties in relation to the court proceedings in the United Kingdom and putting these other cases in jeopardy," Mr Macdonald wrote, according to the Financial Times.
Efforts by the BBC's Abuja bureau to interview Mr Aondoakaa have proved fruitless.
In a subsequent interview with Nigeria's Leadership newspaper Mr Aondoakaa made clear that one of his concerns was that the letter requesting assistance was not signed personally by British Home Secretary Jacqui Smith, but by a state lawyer.
"The law that gave me the power of Mutual Legal Assistance says the Home Secretary should send a request.
"A state counsel will send a request to me, not even his Home Secretary, and you want me to sign. No! Are you considering the bigger image of Nigeria?" he said.
British officials have declined to comment on the row - Home Office policy is such that it cannot even confirm or deny that a request for Mutual Legal Assistance has been made.
The UK aims to repatriate to Nigeria all proceeds of crime seized
However, the CPS has confirmed in a statement to the BBC News website, that of eight official requests for assistance from Nigeria, all but the Ibori case and one subsequent one involving an as yet unnamed individual, were acted upon.
In the past it appears that evidence obtained by Nigeria's Economic and Financial Crimes Commission (EFCC), which is investigating 30 out of the 36 former state governors for alleged corruption, was made available to British investigators and prosecutors.
Nigerian analysts say that since the appointment of Mr Aondoakaa in July, there has been an internal battle between the office of the attorney general and the EFCC.
Further conflicts of interest have been reported with suggestions that Mr Ibori is close both to Mr Aondoakaa and to President Yar'Adua.