Rt Hon Jeremy Corbyn, Leader of the Labour Party, UK. Chatham House / Flickr. Some rights reserved. 

My heart sank when I read the leaked Labour manifesto with its echoes of the days of beer and sandwiches at Number Ten, or singing the Red Flag in parliament during the Shipbuilding Bill. 

Because however much the current economic model has broken down, and is breaking us all down, that does not justify a return to a past and almost equally dysfunctional world. Labour's commitment to recreating the great dysfunctional state monopolies of the past would do just that. Just take railway nationalisation, for example. I speak as someone who has been closely involved in the campaign against Southern Rail’s complete dysfunctionality. But the real problem there is as much the secretive and useless fist of the Department of Transport as the useless franchisee. I shudder to think what the Department would do if they were wholly in charge again.

What we really need is not a great, amorphous British Rail – which was at least as late and twice as dirty as our current railways – but a mutual solution which gives the users an equal say with the staff as franchisees.

The reason my heart sank is that it seems clear to me that, every 40 years or so, we get a major reset of the UK economic and political assumptions. It happens pretty reliably, and last time was 1979 (before that: 1940, 1906, 1868, 1832). You hardly need a calculator to realise that we are due for a shift.

The danger about going back four decades, rather than forward, is that this shifts nothing. It simply invites a reaction back to the hopeless and destructive system we have now. We urgently need to go forward, not hanker for the past.

Yet the left has got mired in nostalgia, and it appears to affect all the parties on that side of the political divide. Left candidates ‘defend’ things. They ‘fight’ things. They struggle against things. They oppose – they don’t propose. I’m not suggesting that there is nothing worth fighting, but unfortunately the fight is doomed unless it is also for something.

Yet the left has got mired in nostalgia, and it appears to affect all the parties on that side of the political divide. Left candidates ‘defend’ things. They ‘fight’ things. They struggle against things. They oppose – they don’t propose. 

I don’t mean philosophical abstractions – the equality of humanity, for example. Nor do I mean minor tweaks to a basically Conservative budget, like more money for schools and the NHS – though I would subscribe to all that. We are in search of something else: a new economic model – a mainstream understanding about how potential policies might fit together to create prosperity.

This does not mean more welfare. The last four decades have seen a constant confusion on the Left between the two, imagining that economics was really about extending the safety net. This fails to understand that people want basic independence as well as support, and an economy that means they do not have to rely on handouts. This failure has handed the prosperity card to the right by default.

As we approach the forty-year shift mark, these issues suddenly matter intensely. Because, if the Left just looks backwards to a rosy glow marked 1940 (or worse, 1917), they will hand the next four decades to the right as well as the last four. 

What Jeremy Corbyn’s rise has done, and I don’t underestimate his achievement, is demonstrate a hunger that people have for an economic alternative. And when people want things in those numbers, they will eventually get it. The question is what kind.

On the face of it, the door is ajar for something new and effective. Not even the Conservatives really believe any more that the old trickle down model actually works. They don’t even believe it in the Treasury. But it continues, partly because the whole structure of government is predicated on it, and partly because the left seems unable to boldly go – well, anywhere really.

Wherever that is, we will have to find solutions that derive from three critical and urgent problems.

1. How can we provide prosperity for the vast majority of people without bringing climate change disastrously down on our heads?
2. How do we unleash the enterprising spirit in communities so that they can begin to support themselves, without those ventures being squashed by the new class of international monopolies?
3. How can we build local institutions that work for people better either than the absentsee privatised giants or the public sector megasaurs that I remember from my own dawn of time. The Central Electricity Generating Board, the Department of Health and Social Security were some of the least responsive beasts ever invented. God save us from their rebirth, making meals of their own tails.

So if forward-looking, local economic solutions are my key issues, then I will be voting Liberal Democrat, even though I am aware that this is not the whole answer.

If you read the manifestos closely, both Labour and the Liberal Democrats are finally happy to confront the big banks – though neither have dared do so until recently. I like both commitments – Labour to break up RBS, and the Lib Dems promise to force the big banks to set up a new local banking sector which can provide the local economies with the services the banks no longer able to provide.

No, it isn’t enough. But might it be too much to ask both parties to co-operate in parliament to make this happen?

Or is that too radical? Co-operate in parliament? Whatever next?