At first blush electronic voting sounds like a good idea. To a web-surfer voting online appears no different to shopping on the internet. But in fact the two are poles apart, when people become more aware of the problems with e-voting, they tend to be much more suspicious.

This change in perspective has recently been happening around the world. As the vulnerabilities of their e-voting systems are made clear, countries who had introduced e-voting without much thought or debate have begun to see doubt engulf their electoral systems.

Ireland has a complete moratorium on e-voting following an independent commission's investigations; troubled elections in the province of Quebec led to an indefinite moratorium on the use of e-voting; the Netherlands withdraw one model of e-voting machine after researchers revealed major flaws in a competing model; Italy have just announced that they will no longer pursue e-voting after doubts were raised over the results of their last general election.

In the United States, the home of introducing technology to elections, citizens are reeling from a cascade of disclosures over the insecurity and vulnerability of their systems. The film Hacking Democracy broadcast by the HBO network just before the US mid-term elections took the frenzy of citizen outrage to a new high.

Following the elections the influential National Institute of Standards and Technology released a firm report, which said that electronic voting machines 'in practical terms cannot be made secure'.

E-voting is a very difficult technical challenge because, unlike with ecommerce, the vote must be secret and the voter must be anonymous (unless revealed by a court order due to an old requirement in UK election law).

In ecommerce transactions we willingly tell the vendor who we are and where we live to help mitigate fraud. With elections, votes need to be secret to protect us from vote buying, coercion and invasion of our privacy.

But when the votes are secret how do we know the system has stored the vote as we intended? It would be trivial for an e-voting system to change votes. We would never be able to see what had happened. Even worse, the opportunity to remotely change huge numbers of votes undetectably is for the first time made possible by e-voting.

Paper has properties that we know and understand. It is very hard to carry around one million pieces of paper. Changing the marks on a piece of paper leaves evidence.

Once the paper is in the sealed and watched ballot box we can be confident that our ballot will remain unchanged until the count. It is because of these properties that recent postal vote fraudsters in Birmingham and Blackburn were caught.

Elections and democracy work because our society has faith in the integrity of the electoral system.

Electronic voting's many problems, which I cannot hope to cover in the limited space of this column, provide ample opportunity for growing doubt in the electoral system and its results. So instead of increasing political engagement introducing e-voting risks having even more people lose faith in our democracy.

As IT professionals we have to be clear when new technology isn't appropriate or could be done much better. Using technology to improve NHS care is a good idea, but perhaps how it is being implemented needs work. In the case of e-voting it's a bad idea and we need to call for a stop.

The government has announced plans for e-voting pilots in the May 2007 local elections. We are waiting for the Department for Constitutional Affairs to announce which authorities have been approved to go ahead with which vendors.

While we wait, it is important that this issue, which runs to the very heart of our democracy, is raised with politicians who are often blissfully unaware of what is happening with the voting system.

You can act now by writing to your MP using raising the problems with e-voting as detailed on the Open Rights Group's e-voting page.

Jason Kitcat MBCS researches e-government and e-democracy at the University of Sussex. He is the e-voting campaign coordinator at the Open Rights Group (