The estimate may reflect sellers' hopes that higher banding will mean a higher price. Or it could be snobbishness.
Under the tax, each home is placed in one of eight bands, based on its value in April 1991. Appeals could be lodged formally after 1 April, but last December the Department of the Environment asked councils about the inquiries they had received.
Ealing, in west London, reported that about 30 per cent of inquirers said their property had been valued too low. In Dover it was 25 per cent. These are considered to be over-estimates, but ministers believe that the overall figure could be 15 per cent.
Martin Pilgrim, of the Association of Metropolitan Authorities, said the difference in payments between bands could be small. 'If it might influence the amount of capital which can be realised it might be worth appealing.'