What are the Lib Dems for?

The party's task in Brighton will be to answer that question more clearly

As the Liberal Democrats gather in Brighton, the usual media hue and cry will go up: what on earth are the Liberal Democrats for? Do they have a strategy or even a message? Even worse, are they being squeezed by the sudden chase to the centre ground by Labour and the Conservatives? What is left that is distinctively Liberal Democrat?

To some extent, all parties' support is driven by dislike of the alternatives. But the electorate has to have a sense of the party's values, and the Lib Dems have set out to sing plenty of rousing and distinctive hymns in Brighton. Until the Iraq invasion, both Lib Dems and Labour stood four-square behind the international rule of law as a defining feature of a progressive foreign policy. It remains an outrage that we opted for force in Iraq rather than due process at the United Nations. With the Prime Minister still wobbling between Washington and voters who want out, Ming Campbell will insist on setting a date for withdrawal and highlighting the importance of a two-state solution for Palestine and Israel.

But the principal theme at Brighton will be to press for action on the environment. The Liberal Democrats will debate the first and only comprehensive plans to cut carbon emissions across the whole economy. The Lib Dems propose shifting new car purchases to fuel-efficient models by setting vehicle excise duty on new gas guzzlers at £2,000 a year, and putting up taxes on aviation emissions. Green mortgages would improve the energy efficiency of our homes, where the average energy bill is nearly £400 a year more than it is in chilly Sweden. Renewables need to be given a serious lift as an alternative to nuclear.

By contrast, it was Gordon Brown who scuttled in the face of the fuel-duty protests, and has been cutting green taxes ever since: now down to 2.7 per cent of national income from 3.6 per cent in 1999 and the lowest since Margaret Thatcher. It was Brown who axed compulsory environmental reporting by big quoted com panies, and who vetoed the Department of Transport's scheme to shift freight from road to rail by means of a toll (suggested now by the Lib Dems to double rail investment). It was also Brown who cut spending on flood defences and climate research.

Nor can it be right for Labour to vacate the terrain of social justice. It is appalling that non-domicile taxpayers can legally pay nothing on non-UK income, and that City hedge-fund managers pay a lower tax rate than their cleaning ladies. The Liberal Democrats have picked up these old Labour - and social Liberal - themes, and they resonate. The tax plans suggest that low capital gains tax due to taper relief should go. Bumper pension tax reliefs should be restricted to the basic rate. The broadest shoulders should bear the biggest burdens.

If the tax system is made fairer at the top - and greener all the way through - there would be enough revenue to cut the basic rate of income tax to 16 pence in the pound, the lowest since David Lloyd George. Taxes should be fairer and greener, but not higher. There would also be funding for a renewed attack on poverty: one of the key debates will be on a £1.5bn pupil premium to raise individual funding for children from deprived backgrounds.

Of course the government was right to increase spending on public services: education is up 55 per cent in real terms since 1997-98 and health is up 72 per cent. Yet the contrast between the generosity of the resources and the meagreness of the results is startling. Without local accountability to local users, the system is simply too vast to allow decision-makers to be answerable for their successes and failures. Localism is not about decentralising delivery of objectives determined at the centre, but about genuinely handing power to local communities.

Then there are civil liberties: the Lib Dems return to old themes with a debate on the surveillance society calling for the national DNA database to hold only the DNA of those with a criminal record, to ensure that the Information Commissioner is accountable to parliament not ministers, and to regulate the growth of CCTV.

These are all distinctively progressive positions. Why has Labour trimmed so far on the environment, international rule of law, fair taxes and civil liberties? The debate on governance will highlight the need to give every person an equal vote wherever he or she lives, enfranchising the electorate in the core safe seats as well as the Middle England marginals. We need a change in the system, not just the government. You cannot have a fair society without fair votes.

Chris Huhne is the Liberal Democrat shadow secretary of state for environment and rural affairs