DUBAI (BLOOMBERG, REUTERS) - Dubai's ruler Sheikh Mohammed bin Rashid Al Maktoum ordered the hacking of phones belonging to his estranged wife, using the controversial Pegasus spyware made by NSO Group, a London court ruled.

The surveillance of Princess Haya Bint al-Hussein took place with the "express or implied authority" of Sheikh Mohammed, Judge Andrew McFarlane said in a ruling made public on Wednesday (Oct 6).

The couple have been fighting over the welfare of their children after the princess flew to Britain with them in 2019.

Sheikh Mohammed is "prepared to use the arm of the State to achieve what he regards as right," McFarlane wrote in his Wednesday ruling.

"He has harassed and intimidated the mother both before her departure to England and since," said the judge, and "is prepared to countenance those acting on his behalf doing so unlawfully in the UK."

Sheikh Mohammed, 72, denied the allegations in a statement to Bloomberg.

The case concerns "supposed operations of state security" and "it was not appropriate for me" to provide evidence on such sensitive matters, he said.

"The findings are therefore inevitably based on an incomplete picture" and are also based on evidence "not provided to me or my minders," said the Sheikh.

"I therefore maintain that they were made in a manner which was unfair."

Lawyers for Princess Haya, 47, declined to comment.

The rulings by one of Britain's most senior judges add to the embarrassment facing the Dubai royal family.

McFarlane ruled early last year that Sheikh Mohammed conducted a campaign aimed at "intimidating and frightening" his estranged wife.

Sheikh Mohammed had stated that it was hard to see how the hacking allegations made a "substantial difference" to the issue of his contact with his children, according to McFarlane.

The judge said in Wednesday's ruling that he considered the matter to be of the "utmost seriousness," saying it may have a profound impact on his ability to trust the sheikh with anything but the "most minimal and secure arrangements" for contact with his children.

Meanwhile, the judge also ruled that Sheikh Mohammed's move to try and purchase one of the most expensive properties for sale in Britain which overlooked Princess Haya's rural estate as a "deliberate" act that was "intimidating".

Agents acting for Sheikh Mohammed were weeks away from exchanging contracts on the 30 million pound (S$55.3 million) Parkwood estate when his team decided to pull out of the deal.

Princess Haya had raised the matter at the High Court as part of the legal battle, according to a published judgment.

Judge McFarlane, President of the Family Division in England and Wales, has previously ruled that the Gulf ruler had waged a threatening campaign against Princess Haya since she fled to England in 2019, said she justifiably regarded the property move as frightening.

"There can be no doubt that this deliberate behaviour, both in negotiating a purchase and then withholding information about it, by those who are acting for the benefit of the Dubai ruling family, will have had the effect of intimidating this mother to a very marked degree," the judge said in a ruling published on Wednesday.

"It feels like I am being stalked... the prospect of Sheikh Mohammed, or those on his behalf buying the properties around Castlewood is terrifying and utterly wearing," the princess said in a written statement to the court.

Her lawyers said they first became aware of the sheikh's plans in late 2019, and unsuccessfully sought confirmation from his legal team that he would not to buy any properties near her Castlewood home in Berkshire, close to Windsor Great Park where Queen Elizabeth's son Prince Andrew's home is located.

In late 2020, Princess Haya received information that a trust connected to Mohammed was trying to buy the 29-ha Parkwood estate immediately abutting Castlewood, which had been left to her by her father, the late King Hussein of Jordan.

After the sheikh's lawyers failed to reply to requests from Haya's legal team about the intended purchase, in November 2020 they responded to a direct request from the High Court to confirm the trust was in the process of buying Parkwood and it might well take place in the next few weeks.