Business reporter, BBC News
Barclays says it has globally applicable anti-money laundering policies
Barclays Bank has had dealings with one of the world's most corrupt regimes, according to a report by the the anti-corruption campaigners Global Witness.
It says Barclays held an account for the son of the president of Equatorial Guinea long after evidence emerged that his family looted state oil revenues.
Barclays says it operates a global anti-money laundering policy.
It says it complies with "its legal and regulatory obligations in all jurisdictions in which it operates."
A US bank was closed down after it admitted breaching money laundering laws in its dealings with the regime.
The US bank, Riggs , based in Washington, DC, collapsed in 2004 after it admitted its dealings with the rulers of the country had breached US money laundering laws.
But Global Witness says that in 2007, the son of the president of Equatorial Guinea, Teodorin Obiang, still had an account with Barclays in Paris.
It says a police dossier shows that a cheque drawn on the account had been used to help buy a Ferrari 550, part of an "extravagant collection" of eight luxury sports cars he bought in France over a period of eight years.
Global Witness says Teodorin Obiang earns only $4,000 a month as minister in his father's government, but enjoys a playboy lifestyle, including a mansion in Malibu.
Teodorin Obiang has a luxurious lifestyle
It says anti-money laundering laws required banks to carry out "due diligence" to identify their customers and turn down illicitly-acquired funds, and queries what checks Barclays carried out on him, and whether it had ever filed any suspicious activity reports in relation to his account.
In a statement Barclays said: "Customer confidentiality precludes us from commenting on any specific relationship or transaction or, indeed, whether we have entered into a transaction or provided financial services to a person or entity.
"We confirm that the Barclays Group has globally applicable Anti-Money Laundering policies aimed at complying with its legal and regulatory obligations in all jurisdictions in which it operates."
The case is highlighted in the Global Witness report called "Undue Diligence" which details other examples of banks dealing with suspect regimes.
President Obiang has ruled his country since 1979
It claims that dozens of British, European and Chinese banks have provided Angola's opaque national oil company with billions of dollars of oil-backed loans.
Gavin Hayman, Campaign Director, said: "The same lax regulation that created the credit crunch has let some of the world's biggest banks facilitate the looting of natural resource wealth from poor countries.
"If resources like oil and timber are to truly help lift Africa and other poor regions out of poverty, then banks must be made to stop doing business with corrupt dictators and their families."