John Prescott has told tax inspectors to use satellites to snoop on householders' attempts to improve their homes.
Images of new conservatories and garages taken from space will be used to hike up council taxes and other property levies, official guidance obtained by The Independent on Sunday reveals.
Mr Prescott's department is overseeing the creation of a database containing the details of every house in Britain to help tax inspectors to assess new charges.
Even minor improvements, invisible from the road, will be caught by "spy in the sky" technology that uses a mix of aerial and satellite images taken over time to spot changes.
Last night the Tories accused the Deputy Prime Minister of laying the ground for a "new stealth tax on home improvements".
Houses in the country will be particularly targeted. "Aerial photographs are very effective in rural areas where improvements are hard to see from the road," a handbook for property inspectors says.
The Tories warned of a Big Brother-style inspection regime which could see householders forced to reveal every detail of their homes, including the finish of a children's playroom or the type of central heating.
They accused the Government of using satellite technology to spy on families so they can levy stealth taxes.
Caroline Spelman, shadow Secretary of State for Local Government, accused Mr Prescott of invading people's privacy.
"The public have already expressed concern at the prospect of inspectors with cameras entering their homes. Now it appears that the Government will also be using aerial photography to invade people's privacy and lay the ground for a new stealth tax on home improvements," she said. "For many people who need more space but can't afford to move to a bigger house, the answer is to make improvements to their existing home, but it now seems they are going to be penalised for this through council tax hikes. It is catch-22, with home-owners being taxed if they move and taxed if they don't."
The Government is planning to compile a database of every home in Britain, which will include details of how many bedrooms each house has and what kind of roof it has.
Inspectors will look at whether garden sheds have been converted into offices or studios and whether kitchens or porches have been extended. They will even be able to see if a drive has been Tarmacked or a shrubbery extended. The computer system will be used to assess council tax, inheritance tax and capital gains tax.
A re-evaluation of property values will take into account home improvements, including extensions and conservatories to assess how much council tax a property should pay.
The Government has delayed re-evaluating property values after widespread concern that it could lead to a massive rise in council tax bills, which would particularly hit pensioners.
But the Government's Valuation Office Agency is still rolling out a "Computer Assisted Mass Appraisal" database across England. So far almost two million homes in England have had "value significant codes" recorded.Reuse content