A wall of Middle Eastern and Russian money has helped push the price of a top-end house in London up 46 per cent in the past two years, a rate of inflation four times the national average, according to Financial Times research.

Not every top-end sale appears in the official residential Land Registry data base. Those bought by companies, a route chosen by wealthy people to secure anonymity and financial advantages, are excluded. In order to minimise the volatility that can result at the very top end, the FT examined the price of the 10th most expensive registered property sold each year.