The billionaire ruler of Dubai is battling his wife for custody of their two children in a London court, in what is set to be one of the most expensive and fiercely contested such cases in UK history.

Sheikh Mohammed bin Rashid al-Maktoum has made an application to divorce his wife of 15 years, Princess Haya Bint al-Hussein, in the Family Court Division of the High Court, which will be heard by Sir Andrew McFarlane, its president, on July 30.

Both sides have appointed some of Britain's best-known lawyers.

Princess Haya, 45, the sister of Jordan’s King Abdullah and the most glamorous and visible of the sheikh’s six wives, reportedly left the royal palace in Dubai last month for Germany.