Sheikh Khalifa bin Zayed al-Nahyan owns a secretive property portfolio worth 5.5 billion pounds

Court filings and analysis of public records cited by the UK’s Guardian newspaper showed that among the buildings which form part of Khalifa's property portfolio were Berkeley Square in Mayfair and the freehold of 95 buildings surrounding it and One Kensington Gardens and a residential block in Knightsbridge housing the Ecuador embassy, where WikiLeaks founder Julian Assange took refuge for seven years.

Despite its conspicuous addresses, the owner of the property portfolio kept secret for decades, the report said. 

The property portfolio "was created in a subterranean way through stealth-like deals, quietly put together over many years,” the Guardian cited a source familiar with Khalifa’s business dealings as saying.

Transactions were conducted secretively through a group of companies based in the British Virgin Islands, and handled by lawyers from elite UK firms, who were careful never to name the UAE president, simply referring to him as “The Client”.

According to the report, Khalifa’s London real estate empire surpasses even that of the Duke of Westminster, who owns swathes of the city.

Some reports said Khalifa, who was re-elected as UAE president in 2019, has been “mentally incapacitated” since a stroke in 2014, claims his lawyers have dismissed.

Lawyers for his former property managers, Lancer, say Khalifa’s family members compete for control of his assets, citing a document they claim shows control of his assets was secretly handed over to a special committee, headed by Khalifa’s half-brother Sheikh Mansour bin Zayed Al Nahyan, in 2015.

Lawyers acting for Khalifa have denied he has “surrendered control of his assets”.

The notarized document purports to be signed by Khalifa, but according to the report the signature appears to belong to his brother Sheikh Mohammed bin Zayed Al Nahyan, the crown prince of Abu Dhabi, the de facto leader of the UAE.