Relatives and associates of the late Nigerian dictator Sani Abacha (pictured) have failed to 'unfreeze' £23 million located in the UK in response to a request from US authorities on the grounds that the terms of the requesting letter are secret.

There seem to be two stages in the case. Last July, a High Court judge called Foskett signed an order under Part 4A Proceeds of Crime Act 2002 (External Requests and Orders) Order 2005 (SI 2005 No 3181) that prohibited a certain party (presumably Mohammed Sani  Abacha, the second  son  of  General  Abacha) from dealing with monies (or possibly a portfolio of assets) to the value of £23 million that were in the UK. This was in response to a request from the US Department of Justice by way of the UK's National Crime Agency.

The Abacha party (which might have included Abubakar Atiku Bagudu, an old associate of the general's, and some related companies incorporated under the laws of Singapore whose shares are owned by the trustees of discretionary  trusts) appealed, seemingly on every ground possible. It argued at one point that the US proceedings were invalid because they were not in line with UNCAC (the United Nations convention against corruption) although they purported to be. The US proceedings were part of the federal Kleptocracy Asset Recovery Initiative.

The principal allegation of corruption made in the US proceedings is described as a "security votes fraud", which allegedly involved the theft of more than US$2 billion from the Central Bank of Nigeria under cover of instructions approved by General Abacha, which were issued on the false basis that the money was required for emergency security purposes. The Americans allege that the money so obtained was then laundered through the purchase of Nigerian Par Bonds, US dollar-denominated securities whose interest payments were guaranteed by the US Treasury.

The Abacha party also, and more importantly, applied to the High Court to order the NCA to hand over the American letter of request, which the agency had refused to do voluntarily as the Americans had told it that the letters should be 'confidential.' The Abachas argued that in the absence of such a disclosure the prohibition order should be null and void. There was no legislative requirement for such a handover; their argument instead was that inspection was necessary for the fair disposal of the action.

In January Mrs Justice Elisabeth Laing of the High Court (Administrative Division) ruled against them, pointing out that communications between foreign states were confidential for reasons of 'international comity.'

Nigerian assets have a long history of finding their way to British shores. An estimated £780m of money stolen while General Abacha was in power is thought to have been laundered through British banks. Abacha is said to have died in his holiday home from a heart attack with a bevy of his own private concubines in attendance. British police think that James Ibori, the former governor of Delta State in Nigeria between 1999 and 2007 who pled guilty to ten counts of money laundering, embezzled £150m of Nigerian public funds. Press reports from the Ibori court case revealed that he bought a house in Hampstead in North London for £2.2 million and a property in Shaftesbury in Dorset for £311,000.

Last but not least, Diepreye Alamieyeseigha, the governor of Bayelsa State in Nigeria between 29 May 1999 and 9 December 2005, was detained in London on charges of money laundering in September 2005. At the time of his arrest, the Metropolitan Police found about £1m in cash in his London home. He was found to own properties in London worth an alleged £10 million.