Edward Davey, Liberal Democrat shadow chief secretary to the Treasury, said, "80,000 people are using the system, which cost £17m to implement over three years." The £212 cost per person is nearly four times higher than the £60 per person cost of the existing system, he explained.
Davey accused the Government of failing the taxpayer with the costs involved in the online tax return system. "We all want the Government to use technology for the benefit of the taxpayer. But by failing to deliver a successful project the Government is actually letting down the taxpayer," he said.
"Only New Labour could make a cost-cutting exercise more expensive than the original system."
The Revenue is seen as the standard-bearer in the drive to develop public services that can be accessed by PC or telephone. However, in February the National Audit Office reported a disappointing take-up of the online self-assessment service.
The Inland Revenue was unavailable for comment at the time of going to press.