George Osborne has messed the economy up. This might be a somewhat laconic summary of the latest IMF report into the state of the UK economy, but it isn’t a million miles from the truth. The overly rapid imposition of fiscal tightening has led to recession, which in turn means that borrowing is increasing, not falling. Cue ominous orchestral strings.

Yet as George Eaton argued yesterday, Osborne’s failure - and it is an abject, historic, world-class failure – has difficult political consequences. The Chancellor's failure means the next election will be fought under economically cloudy skies. The economy will probably be growing anaemically by 2015, but there will be pressure on living standards and stubbornly high unemployment. Our national debt will still be rising and the necessary return to fiscal balance will be several years off.

So the government has quietly kicked rebalancing a little longer down the road. The IMF reminds us that the government has already announced "further, unspecified consolidation in 2015-17.". That’s the £10 billion of further welfare cuts the government has "planned" for after the next election. The IMF think growth will be slower than the Office for Budget Responsibility (OBR) does, and deficit targets missed, which means even more "unspecified consolidation" will eventually be needed. To this gloom, the OBR adds that an aging population means return to pre-crisis levels of debt will require additional spending cuts or tax rises worth some £17 billion a year[1] just to return to the debt status quo ante.

These problems are going to land right in the lap of the next government. So what can Labour offer a nation facing weak growth, high debt and demographic cost pressures?

One reaction to the triple squeeze a Labour government would face is to deny that deficit reduction will be needed, that we can find a path to growth in the rejection of spending restraint, or "austerity-lite". In the short-term, that is absolutely the right approach. Debt is historically cheap, and rates are low because money is seeking out the safehouses of government securities. Unfortunately, Labour will not be governing in the short-term. Come 2015, while fiscal consolidation might be slowed, or even temporarily reversed, at some point it will need to be resumed – at least if we are to remain good Keynesians. So in order to create the space we need to invest for growth, we will need to bind ourselves tight to medium-term deficit reduction.

Another argument might be that Labour should support deficit reduction, but primarily through tax increases. If we were to take the current projections, we’d be looking at an immediate £10 billion in tax increases to fund welfare, plus whatever action we took on medium term debt, plus any other cuts we sought to reverse or delay. Then there’s social care, which might need another £10 billion or so. Yet as those dangerous right wingers at the Fabians have pointed out, there is little public appetite for tax rises. Gulp.

I believe neither argument is wholly convincing because neither postponing the debt reckoning nor increasing taxes to preserve services, can renew our national economy. They are responses to problems, not a search for a solution. Instead, our political focus must be directly on the need for the recovery of our national productive capacity.  Naturally, that means we can’t afford the risk of a fiscal event, or to waste money on financing extended debt levels for longer than strictly necessary. So a steady return to fiscal balance is vital. But as well as closing the existing deficit, we also have to do new things to support growth- such as a National Investment Bank, infrastructure, R&D, and education.

Unfortunately, few of these things are free[2]. It is disturbing to think that the key to Britain’s long-term growth is a plan for national renewal which will cost more of the money we already don’t have. No wonder the latest buzz phrase among left-wing wonks is "switch spend" which translates as "cut services to fund investment".

The next Labour government won’t be able to choose between higher taxes and cuts if it is to slowly reduce the deficit, deal with demographic pressures and deliver sustainable growth. Instead, it will have to do both. But how can such a programme ever be sold to an already sceptical electorate?

I believe we need to make national renewal our essential governing project. Our argument must be that national renewal only works if pursued for the long-term and alongside a politics of common sacrifice. The problem for this government is that they do not believe in restraint in any terms other than for the state. If you have wealth, or power, or privilege, restraint is for other people. Labour can offer a distinctive message. Yes, the next few years will be tough if we fight back to economic strength. But we can only do so if all parts of society contribute.

This requires that we change too. If we are to talk of a common purpose, it must demonstrate that restraint is broadly shared. If the risk for the Tories is that they are too indulgent to the wealthy few, then for the left it is that we are unable to be frank with those the trade unions represent. This strategy is risky, I freely admit. It doesn’t sit well with progressives to promise pain today but joy deferred. It will be hard to make the argument to Unison and the GMB that to support long-term growth requires short-term restraint in public service budgets.

Yet the reality is that a Labour government will face sharp constraints, that we need long term sustainable private sector growth to fund our social aims, and that future demographic pressures require more fiscal restraint, not less. That means that a future Labour government would have to make such arguments, like it or not.

Today, politics often sounds tinny and inadequate to the challenges we face.  Perhaps the key to changing that is to frankly recognise the sea of troubles we face, set a great national ambition, and argue that to achieve such may be difficult, but is also worthy. Shared sacrifice, national renewal, common purpose. Maybe it’s just me, but I can see that catching on after selfish Toryism fails.