There has always been a funny smell about the 2007 sale of Sunninghill Park, the house near Windsor Castle that was given by the Queen as a wedding present to Prince Andrew.
The 12-bedroom property, nicknamed 'Southyork' because of its resemblance to oil baron JR Ewing's vulgar mansion Southfork in 80s soap Dallas, had languished on the market for five years before suddenly changing hands in November of that year.
Its purchaser was listed as an opaque company based in the British Virgin Islands, who for reasons that have never been properly explained decided to pay £15 million ($32m), - £3 million over the asking price.
Rather than being done up, the former royal property was then allowed to sit, empty and decaying, for more than eight years. A couple of months ago, it was razed.
Thanks to the British Press, we by then knew that Sunninghill Park's ultimate owner was Timur Kulibayev, an oligarch and son-in-law of Prince Andrew's friend and goose-hunting partner Nursultan Nazarbayev, the autocratic dictator of Kazakhstan.
We also knew the curious 2007 sale had been negotiated by Kulibayev's business partner, another oligarch named Kenges Rakishev.
The apparent intention was to provide a family home for Kulibayev's mistress Goga Ashkenazi (another chum of Prince Andrew), who had given the oligarch two illegitimate sons.
But why, the inquisitive Press repeatedly asked, had the mysterious purchaser volunteered to pay so much over the odds?
And what, if anything, did he expect in return from his chum Prince Andrew?
At the time, Buckingham Palace was adamant that there was nothing untoward about the transaction.
Indeed, it insisted that Prince Andrew had played no part in the arrangements himself, declaring that it was instead negotiated by a trust headed by the Queen's leading financial adviser, Sir Alan Reid, and a representative of her lawyers Farrer & Co.
"The sale of Sunninghill Park was a straight commercial transaction between the Trust which owned the house and the Trust which bought it," read a statement.
"There were no side deals and absolutely no arrangement from the Duke of York to benefit otherwise or to commit to any other commercial arrangement. Any suggestion otherwise is completely false."
All of which sounds perfectly legitimate. Except for one pertinent point: today, the Mail can disclose that Prince Andrew's private office was in fact intimately involved in helping to flog Sunninghill Park.
His staff went to very great lengths to ensure the sale went through, discussing everything from the mansion's interior design to its security arrangements with the wealthy Kazakhs.
A tranche of leaked emails further reveal the Duke's involvement in a highly unconventional negotiation for his wealthy chums to lease two fields next to the mansion from the Crown Estate, the organisation which manages land on behalf of the British taxpayer.
That deal, by which the existing tenant, a farmer, stood to be turfed off the fields, would have seen the Crown Estate paid just £200 per acre per year by the Kazakhs, a sum described by one Land Agent with knowledge of it as 'something of a peppercorn rent'.
What is more, in the years that followed the transaction, the Prince quietly maintained a close relationship with the buyer, oligarch Timur Kulibayev, and, the Mail can further reveal, made an extraordinary attempt in 2011 to arrange for Coutts, the Queen's bank, to take the Kazakh oligarch on as a client.
The Duke asked if senior figures at the state-owned Royal Bank of Scotland, which owned Coutts, could travel to Kazakhstan to meet the billionaire in order to discuss "wealth management".
His request left the bank in an awkward position, since in the words of a senior source there, "Kazakh oligarchs are the sort of people we generally don't touch with a bargepole".
Indeed, so corrupt is the country, and so kleptocratic its ruling class, that RBS these days refuses to do any business whatsoever there, as a matter of policy.
The extraordinary real story behind the sale of Sunninghill Park comes on the back of the revelation at the weekend that Andrew used his relationship with the oligarch Kenges Rakishev to act as a "fixer" by helping a Greek sewerage company and a Swiss finance house pursue £385 million contracts in Kazakhstan.
Scandalously, the Duke attempted to set up that deal at a time when he was supposedly employed as Britain's roving trade ambassador.
Negotiations over Sunninghill Park stretch back to July 2007, when the Duke's deputy private secretary, Amanda Thirsk, began discussing the finer details regarding its sale with Mr Rakishev.
Like many a wealthy entrepreneur from a former Soviet bloc country, it soon emerged that he was somewhat paranoid about the issue of domestic security.
He was therefore anxious to either buy or lease extra land around Sunninghill Park. Of particular interest were two fields between the house and its nearest road, the B383, at the time leased to a local farmer.
Ms Thirsk, a former banker who has since been promoted to private secretary and is regarded as Prince Andrew's closest aide, duly contacted the Crown Estate, which owned the land. She asked if the potential buyer of Sunninghill Park could take it over.
On July 6, 2007, Philip Everett, the Crown Estate "ranger" in charge of Windsor Great Park, emailed Amanda Thirsk saying such a deal could indeed be struck.
He was 'quite happy to give you draft terms for you to discuss with the potential owner of Sunninghill Park relating to the land on the north-east side of the property'.
Everett would, he said, arrange for the Kazakhs to be given a 'grazing licence', which would allow them effective control over the 5.52 acres of grassland for £200 per acre 'which, in this case, equates to £1,100'.
The existing tenant would presumably be turfed off.
'The grazing licence is for the period of one year, but is normally allowed to run on with similar terms on a year-by-year basis.'
It was, on paper, a highly curious deal, according to a land agent with knowledge of the offer. After all, £1,100 per year is, on paper, a relatively small fee to dramatically enhance a £15 million home.
'For grazing rights, £200 an acre is fair enough,' says the agent. 'But this wasn't really a grazing deal. Here, they were leasing land which would significantly improve the privacy and security of a very expensive private home.
'Normally, you would expect a land agent, which is what the Crown Estate are, to negotiate as much as they possibly can for such a lease.
'Here, it doesn't look like any negotiation has taken place at all. Instead they were prepared to let it go for what, compared to what they could have raised, is something of a peppercorn rent.'
The Crown Estate last week declined to comment on whether the proposed deal represented good value for the taxpayer.
Neither would it discuss whether it was appropriate for them to have offered to lease what is effectively public land to a Kazakh oligarch, at the request of the Duke of York.
In a statement, it would say only that 'no such deal' was ever finalised, and that the land therefore remained in the hands of a 'farm tenant'.
Buckingham Palace denies that the Duke received 'preferential treatment'. Though one wonders whether the Crown Estate would have been so eager to help a Kazakh who didn't have royal backing.
Back to 2007. In the second week of July, Andrew's then deputy private secretary Amanda Thirsk held a face-to-face meeting with the Kazakh financier Kenges Rakishev to run over a number of other details regarding the sale.
Comically, it seems that part of the meeting was taken up by the security-conscious Kazakhs wondering if they would be allowed to install their own gun-toting guards on the premises, a short drive from Windsor Castle.
At 12.49 on July 16, Ms Thirsk emailed them on this point. 'It is not possible to organise armed security in the UK unless it is provided by the police. There is no mechanism that allows payment,' she wrote.
The July 16 email also sees Ms Thirsk advise the Kazakhs on Sunninghill Park's interior design. She suggests that they hire Annabel Hall, the owner of a firm called Private Lives, which had recently been 'responsible for the design and re-fit of Royal Lodge', the Duke's current home in Windsor.
Ms Hall emailed the following week, saying it would be 'a pleasure' to give the property a facelift since it 'needs imaginative transformation from a tired, empty house into a warm and beautiful home for a young family'.
Alas, it was not to be. For reasons that have never been adequately explained, neither Timur Kulibayev - son-in-law of the Kazakh president - nor his mistress, the socialite Goga Ashkenazi, ever took up residence at Sunninghill Park.
Instead, the mansion remained empty and it was effectively left to rot.
Despite the protestations of the Palace, this sparked continued media speculation about the real motivation behind its sale.
Fast forward to the early months of 2011, and with Sunninghill Park still empty, the Duke of York made an extraordinary attempt to help his friend Mr Kulibayev become a client of Coutts.
In March that year, the Court Circular recorded that Prince Andrew met with Rory Tapner, the bank's CEO, who was also head of RBS's wealth management division.
A fortnight later, the Duke then emailed the Kazakh oligarch Kenges Rakishev in an attempt to set up a meeting between Timur Kulibayev - the purchaser of Sunninghill Park - Rory Tapner and an RBS colleague called John Hourican.
'If possible, I would like to have the CEO of RBS Wealth, Rory Tapner, and John Hourican, CEO Global Markets, come to Kaz [Kazakhstan] to see TK [Kulibayev] with a view to discuss [sic] Wealth Management and GBM [Global Banking Markets],' wrote Andrew, whose emails when they appear in an inbox rather amusingly say they are from a sender called 'The Duke'.
'Otherwise it could be arranged in London at TK's [Kulibayev's] convenience when or if he comes here next.'
The Prince's intervention threatened to leave the bank in a tricky position. 'This was not, to put it mildly, a meeting that we would have been keen to take,' says a source there.
'Kazakh oligarchs are the sort of people we generally don't touch with a bargepole, regardless of how keen the Duke of York is for us to bring them on board.
'There are too many of what one politely calls compliance issues regarding the source of their enormous wealth.
'Also, Coutts has a policy of not bringing in new clients on the basis of referrals.
'It can create awkwardness if you decide to turn them down. So the bank would never have asked Prince Andrew to set up this kind of meeting, or have agreed to him sending an email like this.'
Little wonder that the mooted meeting never took place, meaning that the Prince's hopes that Mr Kulibayev would become a client of the Queen's bank came to naught.
Strangely given Coutts' policy on Kazakhstan and referrals, the Palace suggested last night Prince Andrew had sent the email as a favour to the bank.
'The Duke of York works to encourage economic growth in the United Kingdom and from time to time he is called upon by UK companies who wish to make contact with overseas markets,' they said, in response to an inquiry about the email.
Asked to comment on what Ms Thirsk's emails reveal about how intimately the Prince's private office were involved in the sale of Sunninghill Park, a spokesman said the Palace stands by its statement distancing Andrew from the matter.
Quite how it justifies that position is anyone's guess. But the public will surely reach its own conclusions.
For, as we have seen, the written record of what took place during this strangest of property deals tells a very different story.