Image copyright Getty Images Image caption Ruben Vardanyan when still head of Troika, at the St Petersburg International Economic Forum in 2010

An investment bank led by an oligarch who collaborated with Prince Charles on charity work managed a network of offshore companies moving billions out of Russia.

An international investigation has exposed how the network received money from companies linked to major fraud.

The oligarch, Ruben Vardanyan, is the former boss of Moscow investment bank Troika Dialog.

He says he was not involved in the bank's day to day operations.

Money from the network was sent to the Prince's Charities Foundation to help restore Dumfries House, a stately home in Ayrshire.

The prince's charities said they had subjected Mr Vardanyan's donations to robust due diligence and no red flags had been raised.

Image caption Dumfries House

The web of more than 70 offshore companies is exposed in a leak of 1.3 million confidential bank transactions to the Organised Crime and Corruption Reporting Project (OCCRP), a consortium of east European investigative journalists who shared information and documents with the BBC and the Guardian.

Between 2009 and 2011 the Prince's Charities Foundation received three payments, adding up to $202,000 via a now-defunct bank in Lithuania.

The leaked bank data show the last of the payments went to an account held by the Prince's Charities Foundation.

The payments were from a company called Quantus Division Ltd, which is revealed today to have been part of a network of offshore companies that sent billions of dollars out of Russia.

The network was managed by a Moscow investment bank, Troika Dialog, whose chief executive at the time was Mr Vardanyan.

Mr Vardanyan says that as well as being Chief Executive, he was also a private client of Troika Dialog and any donations to the Prince's Charities Foundation were from his personal funds.

Over the years, Mr Vardanyan enjoyed an ongoing charitable and business relationship with the Prince of Wales.

In 2010, Mr Vardanyan attended an event celebrating Armenia and its culture at Windsor Castle where the Prince spoke about Dumfries House and his plans to restore it.

The Troika Network

Most of the leaked records are from the Lithuanian bank Ukio Bancas, shut down by the Lithuanian authorities in 2013.

Between 2005 and 2011 more than €3.35bn was moved into a network of offshore companies managed by Troika Dialog and €3.5bn was moved out.

The companies appear to have been used to move money anonymously.

The Troika network of companies was set up as a service for clients, many of them members of Russia's elite, to move money around the world for both business and personal use.

They used some of it to pay for everything from properties in the UK to luxury yachts, artwork and World Cup tickets.

Ruben Vardanyan and his partners made $1bn between them in 2011 when they sold Troika to Sberbank, owned by the Russian state.

A spokesperson for Sberbank said that the company did not participate the transactions uncovered in the investigation.

Documents seen by the BBC suggest that companies in the network including Quantus Division Ltd made and received payments said to be for goods such as food, lighting, electronic goods, building materials and even sanitary ware.

However, they were being purchased by companies with no offices, no employees and no trade, suggesting that in reality no such goods changed hands.

Tens of millions

Other bank records show tens of millions of dollars flowing into companies in the network from other companies linked to major crimes.

They include one of the largest frauds to have been exposed in Russia, the $230m tax fraud discovered by Russian tax lawyer Sergei Magnitsky.

In November 2009, nearly a year after reporting the fraud, Mr Magnitsky died in suspicious circumstances in a Russian prison.

Leaked bank records from Ukio Bancas show companies that benefited from the tax fraud sent $123m through the Troika network.

The BBC has seen no evidence that Mr Vardanyan was himself involved in any criminal activity.

His lawyers told us he was not involved in the operations, management or activities of the wealth management arm of Troika Dialog Group, and that he has always acted in a transparent way.

A spokesman for Clarence House said the Prince of Wales's charities operate independently of the prince himself in relation to all decisions around fundraising.

A spokesman for The Prince of Wales' Charitable Foundation and The Dumfries House Trust told us: "The charities apply robust due diligence processes. In the case of the examples highlighted, no red flags arose during those processes. "