In Westminster, where 33pc of homes are likely to have to pay the mansion tax, 6,855 properties in the top three council tax bands are currently charged a second home premium.
A second home in the borough that falls into band H and is charged double council tax paid more than £4,000 this year. Add on a mansion surcharge and it could result in some homeowners paying three times the council tax of others in the same band.
Around 43pc of band H properties across England are expected to be liable for paying the mansion surcharge based on their current valuation, as well as 17pc of band G homes.
But some middle-class families will also be caught by the tax, as 45,000 band F properties are estimated to be worth at least £1.5m.
Although 90pc of the most expensive properties fall within the top three council tax bands, thousands of homeowners in bands A to E will effectively escape the levy, as their homes are not expected to be revalued.
England’s council tax system, which is still based on property values from 1991, is often criticised for its regressive nature. This means that people living in smaller properties often pay proportionally more in tax than those in larger homes.
Tom Bill, of estate agents Knight Frank, said: “There is also a question around band D and E properties being exempt but potentially worth more than those captured in the top three bands.”
London property prices have also raced ahead of those outside the capital over the past three decades. The capital will be hit the hardest by the Chancellor’s proposals, with one in every 15 properties in the capital expected to be in line for the charge.
