A six-bedroom apartment at One Hyde Park, Knightsbridge, has been sold for a record $221 million.

The penthouse stretches across two floors and has bullet-proof windows, a panic room and views across the Serpentine.

One Hyde Park has 86 properties starting at around $30 million.

Real estate professionals say that the super rich – many from oil rich nations in Africa and the Middle East – have been buying luxury properties in London since the beginning of the year as oil prices remain high.