Tim Montgomerie: David Cameron needs to win a mandate and a majority

He must overcome his caution and set out clearly where the axe will fall

David Cameron and George Osborne have spent the last 20 years in opposition or as supporters of very unpopular Tory governments. This backdrop is essential to understanding why the duo currently leading the Tories are still campaigning and strategising as though the election result is on a knife-edge.

Both men have deep scars from three successive defeats. They are still respectful of the Labour machine that crushed John Major in 1997. And aware of the electoral landslide that is needed to put David Cameron in Downing Street, they look at current opinion polls with a mixture of delight and disbelief.

This electoral anxiety, and David Cameron's instinctive moderation, are causing the party leadership to remain coy about how they will restore some balance to the public finances. This is not to say that the rhetoric isn't tough. Osborne has told the nation that the cupboard is bare. Cameron has warned that Britain is on the brink of a debt crisis.

Actions haven't always matched the rhetoric, however. The pledge to outspend Labour on the NHS – opposed by two-thirds of Tory members – is going to require even more painful cuts in budgets like defence, transport and welfare.

At this year's Conservative Party Conference in Manchester – barely six weeks away – the Tory leadership must begin to overcome its electoral caution and set out more clearly where the axe will fall. The resulting candour might not make much difference to the outcome of the next general election but it could be crucial to the chances of a prime minister Cameron being re-elected.

The next government will have to take incredibly difficult decisions on public spending and tax. In order to achieve some sort of fiscal stability, spending cuts and/or tax increases totalling something like £100bn are going to be necessary. The next government can make those £100bn decisions having levelled with the British people or it can make those decisions without a mandate. Without a clear mandate there is going to be little defence against the wave of hostility that will greet the toughest of public spending settlements.

It is the nature of the media that steady progress towards a large goal is under-reported but the costs of getting there are headline news. Specific setbacks produce headlines in a way that general progress does not. While every £1bn improvement in the nation's debt burden will be shared invisibly across the nation, every £1bn of cuts will provoke squeals whenever a library is closed, a train service axed or a benefit frozen.

The next government will be making deeper cuts than any previous government. It will face a public that is less patient (just ask any Premier League football manager). And it will be doing so in the age of the internet.

If the Left has any sense it will rebuild on the internet. The Labour and Liberal Democrats should realise that the age of mass membership political parties is over and that the future belongs to political entities that provide leadership and shape to a rainbow coalition of causes. Building databases and campaigning websites for people opposed to cuts in specific programmes and locations will present an enormous opportunity to build those online movements.

The Conservatives have less than a year to protect themselves from this impatient storm. Part of that protection will come from using the last nine months in opposition to build the party's own online movement but the most important protection will come from having that clear mandate.

Immunity from public anger comes from having a purpose. If you are seen to be vulnerable to the pressure of public opinion you can expect a tougher time from the media and from popular campaigners. Politicians like Tony Benn, Ann Widdecombe, Margaret Thatcher and Ken Livingstone are much less vulnerable to public campaigns because they are seen to have a clear purpose. They don't need to check polls to know their own minds.

David Cameron is a conviction politician – comfortable with all of conservatism's key traditions but he is leaving it late in the day to spell out the tough decisions that he intends to make. His support across the nation is currently wide but not necessarily deep. A clear and positive vision for getting Britain out of Labour's mess will give him the strength of support that he will need for the very tough years that lie ahead.

Tim Montgomerie is editor of ConservativeHome.com