Richard Donnell, Hometrack's director of research, said the problem was supply outstripping demand for homes. He said: "What we call the 'buyer's strike' continues, with a fall of 11.7 per cent in the number of buyers registering with London agents in May. At the same time, the number of homes on the market, which is already greatly oversupplied, grew by a further 5.3 per cent."