Images from Google Earth, which allows users to zoom in on satellite views of properties, give the taxman clues about lifestyles and wealth, such as cars and home improvements.
Officials at HM Revenue & Customs will feed the data into a supercomputer to try to decide whether to investigate homeowners already believed to be paying too little tax.
Google Earth is the latest weapon in HMRC’s battle to close a £35billion gap between what it believes individuals and companies owe and the tax that is actually collected.
It says tax evasion and the hidden economy – customers not paying VAT on home repairs, for example – cost the UK taxpayer £9billion a year. HMRC has spent nearly £1billion over the past three years trying to enforce the rules.
Over the past 18 months, it has set up dozens of taskforces to probe the tax receipts and business practices of industries as diverse as restaurants, private cab firms, hairdressers, outdoor markets, car dealerships and even Avon Ladies.
It has also spent £50million on the supercomputer, which is called Connect.