It’s the economy, stupid! That was the famous slogan written on the war room whiteboard in Bill Clinton’s 1992 election campaign. It’s just as relevant in Britain today and should be at the heart of our Labour leadership choice too.

Labour must not sign up to George Osborne’s ideology of austerity or weak economic plans. And I won’t. We need to be confident enough not to swallow the Tory myths and to set out a strong, radical alternative instead. But it also has to be credible – credible enough to be delivered, and to build public confidence in Labour’s economic approach so we can win, and change Britain’s economic policy in practice. Otherwise it’s not a real alternative at all. And we will let people down.

For a start, that means we have to challenge the Tory rubbish about Labour’s record. As I have always said, it was the financial crisis that caused the deficit, not the deficit that caused the crisis: it wasn’t too many teachers, doctors or Sure Starts that caused global banks to come crashing down.

While there was a small current deficit before the crisis, because we had paid down debt in previous years, we were still strong enough to support the economy, cut VAT, stop the car industry going bust, create jobs for young people and stop banks crashing with our hopes and dreams.

Andy Burnham and I disagree on this. I will not apologise for Labour’s investment in schools and the NHS – that’s what Osborne wants because he wants to blame Labour for the ideological cuts he is making now.

Equally, we cannot swallow Osborne’s austerity obsession and weak economic plan for the future. The chancellor’s proposal to cut 40% from our public services goes way beyond anything needed to get the deficit down – it’s an ideological attempt to shrink the state and our public services. And it’s bad economics too. The deficit and debt need to come down.

But the chancellor is hitting the very skills, infrastructure and childcare our economy needs to grow strongly and increase tax receipts. Further education courses are being cancelled and some colleges are on the brink. The Midland main line and trans-Pennine upgrades to boost the northern economy have been shelved. Childcare support that helps parents work has been delayed.

While many economists agree there should be an alternative to Osborne, they don’t mean printing money to do it

Nor is there any serious plan for good jobs and growth. Productivity has stalled. Britain is getting left behind. Too many people are stuck in low-paid, insecure work. Too many businesses are stuck in a narrow, short-termist frame. Science investment is frozen.

Infrastructure like Heathrow is delayed. Exports have fallen behind and prevarication on Europe is hitting investment too. Osborne’s laissez-faire approach means he won’t take the action needed either to support economic growth or to make sure it is fair for all.

Indeed, Tory policies are widening inequality and increasing poverty, just when everyone from the Bank of England to the OECD is warning that prosperity needs to be shared or it will undermine our economy. Labour doesn’t have to sign up to this. And we must not. But what is Labour’s alternative? Because, thus far, you might think Jeremy Corbyn and I agree. Here’s where we differ – and it really matters. If we’re to take on the Tories and win, we have to be credible in our opposition.

That means we can’t pledge to just print more money year after year to pay for things we want. Jeremy’s plan for quantitative easing for infrastructure won’t work. It’s one thing to use QE to boost liquidity when the economy has crashed. But if you try it when the economy is growing, you push up inflation, destroy confidence in the currency, lose jobs and investment, and create a cost of living crisis too. So while many economists agree there should be an alternative to Osborne, they don’t mean printing money to do it.

Nor can you just make endless policy promises to be paid for by extra borrowing or printing money we haven’t got. Sound public finances matter – the deficit and debt still have to come down. Nor pledge to confiscate assets and companies without compensation – that would hit investment confidence and pensions.

Ultimately, all this would be pulled apart before we even got to the election, undermining our credibility and our chance of standing up for people who need a Labour government. So what is the serious, credible alternative to Osborne? Here are five things I would do.

First, we need a serious growth plan that boosts productivity. We need to work with business to double our national investment in science and create 2 million more hi-tech manufacturing jobs. With a vocational revolution – ending the age-old British snobbery that treats vocational skills as second class.

Second, we need to bring borrowing and debt down in a sensible and fair way, with a clear commitment to sound public finance – but with the confidence to strongly oppose 40% cuts, and maintain support for the economic infrastructure and public services we need.

Third, we must stay in Europe to support jobs and growth – and as an internationalist party we must argue strongly for that.

Fourth, we need wider reforms to the way the economy works. I’ve talked about a more feminist approach to the economy – developing free universal childcare, starting with the money from abolishing the stigmatising marriage tax break. But we should also be challenging the short-termism of what Hillary Clinton has described as quarterly capitalism.

Fifth, we must have an alternative to the Tories’ widening inequality. That’s why I will restore the target to end child poverty in a generation, campaign against the Tory cuts to tax credits, oppose the inheritance tax cuts for the wealthiest estates, and pay a proper living wage to 1.4 million care workers. And I have long argued that a 50p tax rate on pay over £150,000 while the deficit is coming down is fair.

So I strongly believe there is a credible Labour alternative on the economy – that supports new, good jobs for the future, tackles inequality, sustains our public services and brings the deficit down in a way that is fair.

But pretend alternatives won’t work. False promises won’t create good jobs or build public services. And if the public think the only choice is between austerity and printing money, it’s not only Labour that will lose – it will be the public services, our communities and our economy too.