Lord Mandelson is at the centre of fresh controversy over his relationship with the super-rich after being hired by a multi-billion-pound investment company accused of being used by Kazakhstan's autocratic president to maintain power.
The former Business Secretary recently spoke at two events organised by Samruk-Kazyna, the country's sovereign wealth fund. One was in the Kazakhstan capital, Astana, the other in London.
The fund is effectively run by President Nursultan Nazarbayev's son-in-law, Timur Kulibayev, a close friend of Prince Andrew who bought the Prince's marital home for £15 million three years ago – £3million over the asking price.
Influential: Lord Mandelson, pictured with fund chief Kairat Kelimbetov in London, is at the centre of fresh controversy over his relationship with the super-rich
The Labour peer's involvement with the fund will prompt concern that he is cashing in on the extensive contacts he built up working as Gordon Brown's business secretary and as EU Trade Commissioner.
Lord Mandelson was paid by Samruk-Kazyna through Willbury Ltd, a company he set up to collect the proceeds from sales of his autobiography, The Third Man.
Last month his assistant Benjamin Wegg-Prosser set up a company called Global Counsel LLP, which will act as a vehicle for the peer's future consultancy services.
Mukhtar Ablyazov, a former head of the now state-owned Kazakh bank BTA and a political opponent of President Nazarbayev, claims in High Court documents that Samruk-Kazyna is an instrument used to advance the personal interests and political and economic power of the country's leader.
The judge hearing the case, Mr Justice Teare has ruled Ablyazov's assets should be put in receivership because he 'cannot be trusted' to dissipate those that are not his.
He also ruled Ablyazov's passport should continue to be held by the court to stop him leaving the country.
Mr Ablyazov is in exile in Britain awaiting a hearing in the High Court following accusations that he embezzled £1.29billion from BTA. He says the allegations against him are politically motivated and that the Kazakh government illegally took control of the bank he once led.
His defence papers argue that the takeover of BTA by Samruk-Kazyna in February 2009 was 'the culmination of the campaign by the president and his allies to wrest ownership and control of [BTA] from [Ablyazov]'.
The court papers add: 'Samruk-Kazyna is another instrument used by the president to advance his personal interests, including the domination of the economic (as well as political) spheres of Kazakhstan.'
Lord Mandelson attended a Samruk-Kazyna-organised conference entitled 'Strategy 2030: the way to sustainable development' in Astana, on October 15. According to Russian newspaper reports, he lavished praise on the fund, saying: 'I want to stress a special role [it] played as a saviour of the world economy.
'There are at least two British banks which owe their economic vitality to sovereign funds, including those from Kazakhstan.'
It is understood that Lord Mandelson was referring to the vast sum the Royal Bank of Scotland would have lost had BTA not been taken over by the fund – as RBS acquired some of BTA's debts in its purchase of ABN Amro.
In November, Lord Mandelson attended a business forum organised by Samruk-Kazyna in the exclusive Mandarin hotel in Knightsbridge and at Mansion House, where he spoke about his time as European Trade Commissioner and spent some time chatting to the fund's chief executive, Kairat Kelimbetov.
Samruk-Kazyna, which counts former BAE boss Sir Richard Evans among its directors, said Lord Mandelson's experience was 'especially useful' to them but would not be drawn on whether there would be a long-term commercial relationship, nor would they discuss his fee.
However, the fund's managing director, Peter House, said: 'Samruk-Kazyna is seeking to gather leaders and experienced people who can help Kazakhstan in its striving for further development of the economic and business sectors and diversification from the oil-and-gas sector. Lord Mandelson has especially useful experience and has met Kazakhstan delegations several times.'
A spokesman for Lord Mandelson said: 'He was pleased to visit Astana in October. He spoke about the role sovereign wealth funds can play in the global economy. He was contracted to speak through Willbury Ltd.
'Willbury Ltd appears in his entry in The Lords' Register and has been approved by the Cabinet Office. This information is published on the relevant websites.'
A spokesman for the Samruk-Kazyna fund declined to comment on Mr Ablyazov's claims