The former Duke of Palma, Iñaki Urdangarin, has been given until Monday to turn up at jail to start serving a sentence of five years and ten months following a ruling by the Supreme Court on Tuesday.
Urdangarin, who is married to the King's younger sister, Cristina de Borbón, was found guilty in February last year by the Mallorca provincial court and sentenced to six years and three months in the Nóos corruption case for fraud, embezzlement, tax crimes and influence peddling, among other offences.
The appeal went to Spain's Supreme Court which announced this week that it upheld the decision made by the Palma magistrates, differing only in the case of a charge of document falsification and reducing the sentence by five months.
Urdangarin's former partner, Diego Torres, has also seen his sentence reduced by the Supreme Court, in his case from eight and a half years to five years and eight months.
This week's ruling upholds the original verdict that Torres and Urdangarin illicitly obtained public money from the Balearic regional government, among other administrations, using a non-profit organisation, Instituto Nóos. Funds were handed over for the organisation of sports-related events and projects and channelled out of Nóos using a web of cover firms.
The sentence states that Urdangarin used his status as a member of the royal family to obtain lucrative contracts. Officials had been given orders by former Balearics president, Jaume Matas, to approve all of the proposals and invoices sent in by Nóos without questioning prices or concerning themselves with bureaucratic hurdles or legalities.
Matas, the third defendant sentenced to prison in the case, has seen his sentence of three years and eight months confirmed this week.
Both Torres and Urdangarin attended the Palma provincial court, separately, on Wednesday morning to receive their official orders to go to jail. They were both given five days to turn up at the Spanish prison of their choice.
Matas chose to skip that stage in the process and went straight to the Aranjuez prison in Madrid on Wednesday.
Urdangarin, who lives with his wife in Geneva, was allowed to keep his passport to go back to see his family before Monday.
With the Supreme Court ruling, the former duke's chances of avoiding jail have practically run out. The next step in the appeal process would be to turn to the Constitutional Court alleging the violation of fundamental rights and calling for the sentence to be suspended. The likelihood of this however, is remote, as is another last resort, a pardon from the Spanish government.
Speculation is currently focused, therefore, on which of Spain's prisons Urdangarin will turn up at on Monday.
Cristina de Borbón was acquitted of criminal charges by the provincial court last year but given a fine of 265,000 euros as a beneficiary of her husband's illicit business activity. The Supreme Court has reduced her fine to 136,950 euros.