It said the cases of Joshua Darye who was governor of the central Nigerian state Platau State between 1999 and 2006 and Depriye Alamieyeseigha of Bayelsa (governor between 1999 and 2005) demonstrate the vulnerability of the UK’s financial system to dirty money. "With alarming ease the two men opened numerous bank accounts, brought millions of suspect pounds into the country and lived lives of luxury," Global Witness said in its report.

"The escapades of former governors Alamieyeseigha and Dariye have been well documented by the media, both in Nigeria and in the UK, but the disturbing role of the British high street banks that facilitated his corrupt behaviour has gone largely unnoticed," it added.

It said the story of complicity by UK banks was got, "because information on the role of these banks emerged in court proceedings in London taken by the Nigerian government to recover the assets controlled by the governors in the UK."

"We are telling it now because it raises serious concerns about British banks which have done business with corrupt politicians,'' it added, raising concerns on how former governor of Bayelsa state in Nigeria's Niger Delta region, Alamieyeseigha "controlled accounts with RBS, HSBC, Barclays, and NatWest," all UK-based banks.

The watchdog said nearly all of these banks helped former Nigerian dictator Sani Abacha funnel nearly a billion pounds through the UK, causing a fall-out with the Financial Services Authority (FSA), in 2001, raising the need to ensure and maintain strict due diligence by the banks.

Global Witness had written all the banks named in its report prior to publication, but, "none of them would answer specific questions about their role in taking money from Alamieyeseigha and Dariye, " with some of them only replying with general comments on their approach to fighting financial crimes.

Recommendation

"In line with its new proactive supervisory stance, the FSA, and its successor bodies, should ensure that the banks it regulates are carrying out meaningful customer due diligence, especially in relation to PEPs. The FSA should use proactive methods, such as mystery shopper techniques, in order to identify banks that are failing to implement their own policies. The FSA should name and shame those banks that take corrupt funds and are found to have inadequate systems in place," Global Witness recommended.

Progress and possible model

Nigeria has through successful judgments won over £12 million of the two governors’ assets to the country using a legal tool called civil asset recovery. According to Global Witness, "this type of recovering looted assets is also useful when corrupt politicians have stashed assets outside of their own countries."