For several years, politicians have presented IT as a way of providing new services and opportunities. These days, the tide is turning - politicians now seem to have decided the best way to introduce technology to Britain is by presenting it as a way to save money rather than spend it.

This might not be as surprising as it sounds. The major political parties are competing to cut spending ahead of an election, and the huge costs of computerisation projects have made headlines recently. Last week, it emerged that Department of Health officials expect the NHS National Programme for IT to cost as much as £31bn over the next decade, compared with the previously released cost of £6.2bn. Clearly, overspend is a technology issue that will not be going away.

Tony Blair's speech to the Labour party conference in Brighton mentioned the introduction of identity cards, which the Home Office estimates will cost up to £3.1bn. Spending this in the short term will help save money over time, they claim, as it brings together disparate government processes and cuts inefficiency from the system.

The Liberal Democrats oppose ID cards on civil liberties grounds, but are now highlighting the cost as well. "We think there are other things that have far more value than identity cards," says IT spokesman Richard Allan. "You should look at such a proposal as any business would: where would we put the money to achieve our objectives?"

If the objective is better security, the Lib Dems say those billions should be spent on policing. Allan makes a similar argument for his party's support for open source software that is free of licence fees. He believes the state sector can benefit by examining open source alternatives - either by adopting them or using them to extract a better price for proprietary software. Although the government has a policy supportive of open source software, it "has shown insufficient drive in bringing it forward", he says.

Tony Blair also spoke of "ending the digital divide by bringing broadband technology to every home in Britain that wants it by 2008". In the past, bringing high-speed access into the poorest homes could be a costly political exercise. But although 3m families receiving tax credits might receive state help, Labour's main strategy is to persuade the public to pay for broadband.

The selling point will be the one used in the 1980s for home computers: education. The "hard-working families" Labour referred to relentlessly at its conference will be convinced to buy connections to help their children with homework.

Giving away or subsidising PCs would be counter-productive, according to Antony Walker, chief executive of the Broadband Stakeholder Group, which has been discussing the plans, and is funded in part by the Department of Trade and Industry.

The Conservatives, for their part, are not in the game of spending money unnecessarily. They want to increase broadband use through competition among suppliers. Stephen O'Brien, the shadow trade minister, told their conference's parliamentary IT committee (Pitcom) fringe meeting that users should have a choice of "competing but inter-operable networks which do not share the same vulnerabilities", rather than relying on BT's phone lines for their final connection.

O'Brien highlighted unused capacity on other networks: "The cost of opening up half a dozen new national networks with local radio access has been estimated as rather less than the £20bn lifted from the industry," he said, referring to Labour's auction for third-generation mobile phone spectrum.

He added that the last Conservative government had allowed a regulated duopoly in telecoms, with the hope that new entrants, such as the cable companies, would eventually mean the end of a need for a telecoms regulator.

Stephen Timms, who was e-commerce minister until last month's reshuffle, told the Labour conference's Pitcom meeting that his party saw competition as "a means, not an end" - unlike the Conservatives. So the government's new communications regulator, Ofcom, has a duty of care to the citizen, he said.

Timms, now a Treasury minister, defended the DTI, which both Lib Dems and Conservatives would dismantle. "It's a mystery why the other parties are talking about evacuating trade and industry," he said, adding that the department takes "a very big role in bringing the changes we need".