New London Property Guide In 2006, the smallest houses in the street were selling for £5 million while a larger house, Turkish tycoon Halis Toprak's 30000 sqft Toprak Mansion, sold amidst great secrecy to the President of Kazakhstan, Nursultan Nazarbayev, for £50 million in January 2008, making it one of the most expensive houses in the world, as listed by Forbes magazine.