Motorists poured almost £1.6 million into Treasury coffers through speed camera fines in a year.
Critics said the figures from Sussex would fuel suspicion of cameras and contradicted Government promises.
Ministers had said fines would only be used to maintain cameras and fund road safety schemes.
But the Department for Transport was forced to reveal through information laws yesterday that almost a £1.6 million surplus was passed to the Treasury last year.
Some said cameras were Government money-making machines rather than life-saving devices.
Shadow transport secretary Alan Duncan said: "This provides yet more evidence speed cameras are being used as a stealth tax to raise money from hard-pressed motorists at a time of soaring fuel prices."
A spokesman for the Sussex Safety Camera Partnership (SSCP) said most of the surplus it handed to the Treasury came from just one stretch of road.
Temporary cameras on both sides of the A27 Brighton-to-Lewes road trapped more than 12,000 drivers, raising £750,000 in fines.
It was by far the biggest revenue-earning area for cameras in Sussex, accounting for a fifth of all fines in the county.
Yesterday the SSCP said any money it raised over and above the covering of its running costs was handed to the Treasury.
A SSCP spokesman said: "What the Treasury does with the money is a matter entirely for them. But we don't get to see a penny of it."
Nationally, the Conservatives revealed that £114 million was raised by speed cameras in 2003/04, with £22 million being handed to the Treasury.
Before the summer recess, Government whip Lord Davies of Oldham insisted to Parliament that the cameras were not there to make money.
But the Tories claimed that the new figures, released yesterday under the Freedom of Information Act, proved otherwise.
Mr Duncan said: "The public will be staggered to learn that it costs more than £90 million a year to run Britain's speed cameras.
"These figures will fuel suspicions that many of them are being used as cash-raisers not life-savers."
In its annual report earlier this year, the SSCP showed serious injury crashes and deaths were cut by 31 per cent at fixed camera sites and 16 per cent at sites where mobile cameras were used.
A spokesman for the Department for Transport said: "We do not want the cameras to raise money. We want them to save lives. They have been shown to have reduced casualties and the number of people killed on the roads is going down."
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