The worst vehicle I ever bought was a Bedford van with a Guinness bottle label instead of a tax disc in the windscreen. "It appeals to the coppers' sense of humour," said the previous owner, stuffing my £35 into his sock.

Luckily, I never had to test his theory as the van packed up about half an hour later. But I remember that novel approach to vehicle licensing every time I queue in a post office with a V11 form to renew a respectable tax disc. And I wonder why we can't do this simple annual transaction over the internet.

Car tax is an obvious service to e-enable. Car owners and computer owners tend to come from the same social groups. The technology is established. It's also an obvious service to offer via "intermediaries", such as private garages or insurance companies.

Yet the Office of the e-Envoy's latest report on electronic service delivery lamely lists the service as "not e-enabled". While tax discs for cars under three years old are due to be available electronically this year, owners of cars over three years old will have to wait until October to December 2005. That will make it one of the last services to be introduced before the e-government deadline. The Driver and Vehicle Licensing Agency says it is "on target".

Don't shoot the e-envoy. The reason it is taking so long reflects typical government thinking. As far as the Department of Transport is concerned, the tax disc is not for collecting revenue so much as checking a vehicle's documents. It's the only regular check that a car is insured (though not necessarily for the person driving) and, if more than three years old, has passed its MOT. Post office clerks are trained to scrutinise these documents; putting the service on the web would remove this check.

The solution is to make insurance policies and MOTs available electronically. The motor insurance industry already runs a central database, mainly to help police clamp down on the million or so people driving uninsured at any one time. This database contains 28m policies, but is not "real time" - it takes up to two weeks for a new policy to be registered.

For MOT certificates, the new Vehicle and Operator Services Agency plans to have a database ready later this year. The agency is also launching a system to allow people buying an old banger to check its MOT online.

Here's a suggestion. Launch the tax disc renewal e-service as soon as possible. Most people renewing tax already have an insurance policy, so the insurance database doesn't need to be real time. Neither does the MOT database; motorists could be trusted to enter the serial numbers of their certificates, and random checks made.

This approach will be seen in some quarters as a bodge. But e-government needs more visible success stories. To ordinary citizens, a programme that can't e-enable a routine chore such as car tax is about as credible as a beer bottle label in the windscreen.