There were 161,907 separate incidents of rubbish being illegally dumped in the city in 2005 to 2006, which cost the council £4,909,438 to clear up, according to Government statistics.

Fly-tippers struck another 170,570 times in 2004 to 2005, which left taxpayers with a whopping £5,529,643 bill for clean-up costs.

But there was only one successful prosecution for fly-tipping over the entire two year period - and that was the only case brought to the courts.

The figures were revealed by environment minister Ben Bradshaw following a question by Sheffield Hallam's Liberal Democrat MP Nick Clegg - but Sheffield Council today challenged the accuracy of the figures.

Mr Clegg said: "These figures are worrying. Fly-tipping remains a real blight for many communities in Sheffield.

"So it's a disappointment to see that only one prosecution has taken place and no money has been raised in fines from the perpetrators.

"A lot more clearly needs to be done to deal with fly-tipping."

Sheffield Council's Lib Dem leader Coun Paul Scriven said the figures were "shocking" and blamed the Labour council for not getting its priorities right.

"The figure will shock many people, including myself, about just how much money is being spent," he said.

"But many Sheffield residents will not be surprised at Labour's repeated failures in tackling this issue. Time and time again we see them going big on city centre projects but not dealing with day-to-day issues in the local neighbourhoods."

Green Party councillor Bernard Little was also outraged by the scale of the problem.

"I am shocked and it is disgraceful. But in a way it is an inevitable result of our throwaway society," he said. "We need to be much more effective at publicising the outlets for disposing of something once we're finished with it."

Sheffield Council admitted fly-tipping is a significant problem in the city but claims the figures quoted by Mr Bradshaw were "inaccurate" due to changes in how fly-tipping incidents were recorded before October 2006.

Nick Hetherington, the council's head of Streetscene, said: "The number of incidents recorded in Sheffield in past years does not accurately reflect the true scale of fly-tipping in the city.

"The actual cost of removal is much lower here than the national average cost produced by Government. Overall, the cost of clearing fly-tipping in Sheffield is around £600,000 a year - considerably less than the figures being quoted.

"We accept fly-tipping is a serious issue and a blight on the environment, so we have recently invested in new CCTV cameras to begin covert surveillance operations."

Fly-tipping figures for 2006 to 2007 will be published later in the summer and maximum penalties for fly-tipping have been raised from £20,000 to £50,000.