London developers are shifting their focus towards super-sized luxury flats to keep pace with the growing wealth of overseas buyers seeking a safe haven for their cash, charging them up to 70 per cent more for the privilege. "As the level of wealth among the very rich increases, they are rewriting the ‘pied-a-terre' rules," said Rupert Dawes, a partner at international property consultant Knight Frank. Berkeley Group is building flats of up to 4,000 square feet, about the size of one and a half tennis courts, that can be knocked together for buyers wanting an extra-large home. The development, called Ebury Square in the upmarket district of Belgravia, is due to come on sale this summer. The London property market's appeal as a liquid and transparent investment in a relatively stable political and fiscal environment has attracted a wave of overseas buyers during the global financial crisis. Nick Candy, chief executive of Candy and Candy, the development manager for London's luxury One Hyde Park scheme completed a year ago, where the most expensive flat sold for £136 million (Dh765.54 million), said his company was the first to plug the gap in the London market. "The largest flat in One Hyde Park is circa 30,000 square feet which is like a stately home in the sky," he said. Buyers will pay a premium of up to 70 per cent for super-sized apartments depending on the scheme, said Ziad Salem, founder of luxury property specialist Byblos Property, citing the case of the 199 Knightsbridge development in London. "It has a handful of flats between 5,000 and 7,000 square feet, but you will pay £5,000 to £6,000 per foot compared to between £3,500 and £4,000 for the smaller units because you get more space."