Satellite imagery and aerial photos are being used by Government snoopers as part of a council tax revaluation which could see bills soar.

Opposition MPs claimed the 'spy-in-the-sky' surveillance technology was being used to recalculate bills in Northern Ireland, which they said was a 'testing ground' for using the 'sinister' technique in Britain.

Officials are using covert images to spot home improvements such as extensions, swimming pools and garages to justify tax hikes. They are also identifying 'nice' areas with pleasant views, where tax bills will be higher for all properties.

While the controversial reval- Chancellor's on the spies Chancellor's uation is under way in Northern Ireland, Labour insists it will not happen in England until after the next General Election - apparently for fear of a backlash after years of anger over council tax rises.

When the same exercise was carried out in Wales three years ago, average bills rose 9 per cent despite Government promises that it would be 'neutral'.

Critics are convinced the revaluation in England will see similar increases as millions of homes are pushed into higher brackets, particularly in the South, where property prices have risen fastest. Tory local Chancellor's measly the skies government spokesman Caroline Spelman said: 'Labour ministers may claim to have postponed the council tax revaluation, but in reality it is well under way by stealth, with Northern Ireland being used as the testing ground for new technology.

'It appears the Government will be using planes and satellites to snoop on people's homes.' Civil rights group Liberty has condemned the use of spy-inthe- sky technology for council tax purposes as 'a shockingly disproportionate interference with people's privacy'.

Local Government Minister Phil Woolas dismissed the Tories' claim as 'completely wrong'.