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But in 2012, the leaked papers suggest Vladimir Putin got nervous over the trail. Sandalwood was closed soon after, and that section of the trail was moved to Ove Financial Group, also registered in the British Virgin Islands. One company linked to Ove was owned by Putin's former press minister and media expert, Mikhail Lesin. Lesin launched Russia's state TV channel Russia Today before falling out of favour with Putin. You may recall his name - he was found dead in Washington in November last year.

'The appearance of business'

There is nothing automatically illegal about using offshore companies. But closer scrutiny of the transactions raises huge suspicion.

Speaking to BBC Panorama, money-laundering expert, Andrew Mitchell QC, said: "This is not business, this is creating the appearance of business in order to continually move and hide assets."

The documents reveal what appear to be fake share trades. Shares are traded, there are vague "consultancy" services costing several million dollars, and transactions attributed to "compensation" for cancelled share trades.

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So what have these parties had to say about these allegations?

Last week, Sergei Roldugin said: "Guys, to be honest I am not ready to give comments now... These are delicate issues. I was connected to this business a long time ago. Before 'perestroika'. It happened... And then it started growing and such things happened. The House of Music [St Peteresburg] is subsidised from this money."

President Putin's spokesperson, Dmitry Peskov, has so far declined to comment on the Mossack Fonseca leak, and the trail that appears to be so deeply embedded in it. But last week, Mr Peskov accused 'western spies' of an "information attack" against Putin ahead of the elections.

Yuri Kovalchuk's lawyers said "We do not understand why you address these questions to Mr Kovalhuck?", explaining information surrounding Bank Rossiya was already available to the public.

Russian Commercial Bank said it was now under direct regulation from the European Central Bank and therefore the idea that it is, or was, involved in a money laundering scheme for Putin and his circle is "utterly unfounded". RCB said it had already voluntarily provided information about the allegations to the authorities in Cyprus.