Prime ministers like to build big things. They like to wear high-visibility jackets and watch concrete being poured. They like to cut ribbons. And they like a legacy.

Theresa May is different from past prime ministers in many ways, but it seems she shares with her predecessors a penchant for big projects, even in the face of overwhelming evidence against them. In just a few months she has pushed a vote to renew Trident, given the go-ahead to Hinkley Point C and pledged her government’s support for the expansion of Britain’s busiest airport.

Taken separately these decisions are big. Together they tell us about the kind of Britain this government is trying to build, literally as well as metaphorically: a country ill-equipped for the future and that won’t meet its own needs; a nation whose presence on the world stage will be defined by its ability to kill millions; a Britain failing to make the economic transition necessary to free itself from the worst effects of climate change. Communities that get the illusion of control, provided they make the decisions people in power want.

The choices we’re offered say just as much about the Westminster’s mindset as the final outcomes. Do we want Heathrow or Gatwick? Nuclear power or gas? Safety provided by nuclear weapons or the danger of losing them? We weren’t offered no new runways or a truly decentralised, community-owned energy system. The government didn’t ask whether we want the security of not transporting nuclear weapons across our country. And, without a coherent official opposition on these issues, genuine debate about these alternatives is dangerously narrowed.

It’s striking that support for these mega-projects hasn’t only come from the Conservatives and their friends in big business. The Labour party and the trade unions are backing them, too. An old-school consensus has emerged which sees everyone from Unite to the CBI competing over who can shout loudest about the benefits of building big things. Never mind the better choices buried in the process. But the truth is we do not live in an economy with only binary options.

The government could have chosen not to support Heathrow – and instead followed the climate science to its logical conclusion and pledged action to tackle the surging demand for flying from the super rich. They know that 70% of flights are taken by just 15% of people – and that a simple tax on frequent flights could eliminate the need for new runways – but such evidence gets in the way of their love for laying tarmac. They talk of giving people back control: well try telling that to the people of Harmondsworth in west London – whose homes are set to be the collateral from this environmentally disastrous plan.

All of the mega projects, it is the renewal of Trident that is potentially the most catastrophic

The plan to build a new nuclear power station at Hinkley Point is equally reckless. Bill payers will stump up billions for this colossal folly – and precious resources will be diverted away from building an energy system suited to this century.

But of all of the mega-projects, it is the renewal of Trident that is potentially the most catastrophic. The arguments against Trident are well-rehearsed. But the very fact that building a new generation of weapons of mass destruction is pitched by politicians as central to our nationhood should give us pause for thought. What makes Britain need nukes so desperately when almost all other countries on earth maintain their safety without them?

The Labour party’s position on Trident is particularly strange. It has stated that it is in favour of renewal – but the party has a leader who, quite rightly, says he would never fire the missiles if he became prime minister. Both positions have logic to them, but combined in one party and the end point is committing to building a nuclear weapons system based on the (flawed) theory of deterrence but with a cast-iron guarantee that the those submarines will do nothing more than float aimlessly around the ocean, in a constant state of readiness to do nothing. Perhaps one of the new vessels could be called HMS Pointless?

Of course, if we scrap Trident we need to guarantee the jobs and economic security of those working at Faslane, Aldermaston and elsewhere. A “defence diversification agency” would help to ensure a just transition for the people whose jobs are directly dependent on Trident.

It’s not just alternatives to Trident that are desperately needed. Instead of Hinkley, let’s lead the world in energy conservation. Imagine, for example, that home insulation was central to the government’s infrastructure plans. A nationwide scheme to keep people warm, cut fuel bills and tackle carbon emissions would create more than 100,000 jobs across the UK.

Or imagine we redoubled our efforts to lead the world in renewables and energy storage technologies. That would create more jobs than nuclear weapons or power ever will. We know that green energy creates far more jobs per gigawatt and that every community in Britain can create its own power. Our energy system doesn’t have to be centralised, or owned by multinational firms and foreign governments. It can be built in Britain, located in every community and it can be beautiful.

Infrastructure isn’t just about concrete and hard economic growth. It’s about social connections, too. The qualitative growth that could come from a community learning new skills to manage and run renewable energy projects they own. The conversations over fences, in the post office and pub. It’s the ties that bind us – and the networks that make us a whole greater than the sum of our parts.

Indeed, I would argue that our biggest pieces of infrastructure aren’t bridges, or buildings – they’re the welfare state upon which we all rely, and our National Health Service. So when the government tells you it’s investing in infrastructure, and then ministers don hard hats at opening ceremonies, remember what they’re demolishing with one hand as they cut ribbons with the other.

My challenge to both the government and the official opposition is simple: take a step back and think carefully about the kind of Britain we want to build. We’re a small country, but we should be big in ambition. Let’s pause for a moment before we pour more tarmac for more planes to land on, build obscenely expensive power plants or forge our path in the wake of submarines carrying weapons of mass destruction.

This is a fork in the road – and we have a chance to build an economy that not only meets the challenges of the 21st century head-on but creates a better country in the process. Let’s not miss this opportunity.