Two prominent Saudi princes are involved in a London-registered company that supposedly facilitated "money laundering" for Hezbollah in Lebanon and helped smuggle precious stones out of Congo, according to allegations in court documents.
Lawyers for the Saudis have spent a year trying to suppress the papers, including threatening that relations with Britain would be hurt if they were revealed.
The princes - Mishal bin Abdulaziz al-Saud, a former defence minister, brother of King Abdullah and chairman of the country's allegiance council, and his son Abdulaziz bin Mishal - dismiss the claims as fabrications, "extortion" and "blackmail".
They say their former partner, a Jordanian, Faisal Almhairat, "misappropriated" money from accounts, denied them access to company books, shut down the shared business and "interfered with the negotiations" on deals. Almhairat disputes their claims.
In the context of Middle East politics, the suggestion that two prominent Sunni Muslims from the Saudi royal family have been surreptitiously dealing for profit with Hezbollah, a Shia force supported by Iran, is extremely damaging. Hezbollah is designated a terrorist organisation by the US.
The Guardian and Financial Times originally requested to see the court documents - filed as part of a commercial dispute between Almhairat and the Saudis - in spring 2012. On Thursday, the court of appeal finally agreed to their immediate release.
Among other allegations is the claim that at the "instigation" of Prince Abdulaziz, Saudi police issued an arrest warrant for Almhairat and asked Interpol to issue a red notice sanctioning his extradition to Saudi Arabia.
The case revolves around a breakdown in relations between Almhairat and the Saudis. They were business partners in a London registered telecommunications company, Fi Call, whose capital value was £300 million (HK$3.5 billion).
Fi Call was developing a software application for smartphones that would allow users to make free phone calls. The Saudis' shares were mainly held through Global Torch, a British Virgin Islands company the princes are said by Almhairat to control. Almhairat's shares are held by his Seychelles-based firm Apex Global Management.
The dispute, which erupted over allegedly misappropriated money and the sale of US$6.7 million worth of shares, has "thrown up a nuclear mushroom cloud" of litigation, according to Mr Justice Morgan.
The case raises questions about whether the transparency of British justice can be upheld at a time when the Ministry of Justice is inviting wealthy, international claimants to resolve their disputes in London's courts.