Talking about the prospect of a Labour government, some people sound like they are preparing the obituary before they have witnessed the birth. Sir Keir Starmer has yet to set foot in Downing Street and the air is thick with doomsters on the right and gloomsters from the left who have already decided that a Labour government will be an awful let down. The baleful chorus wails that, even were Sir Keir to win by the stonking margin suggested by recent opinion polls, he will struggle to get much done. Before Team Starmer have got their hands on a single red box, the most miserabilist voices declare that failure is inevitable.

Depressive thoughts about what a Labour government will be able to achieve is partly of the leadership’s own making. Rachel Reeves, the shadow chancellor, never passes up an opportunity to look on the cloudy side of the street by emphasising the direness of the inheritance that will be bequeathed by the Conservatives. Sir Keir spends less time trying to enthuse voters with the possibilities of change than he does warning them of how terribly difficult everything is going to be. Rather than promise the sunny uplands, he cautions that there is a “hard road ahead”, making a government led by him sound like an invitation to participate in a gruelling hill marathon.

This breaks the customary rule that it is better for politicians to accentuate the positive. Yet it is easy to see why the Labour leadership has made negativity so central to its message. Shuddering over what Labour will face reinforces its case that the Tories have made an atrocious mess of everything. Dwelling on how tough things will be puts a check on agitation from within Labour’s ranks to be bolder with spending promises. It also constrains public expectations that Sir Keir and his team will be able to deliver swift solutions to the many problems crowding in on Britain. A dour tone is in tune with a sour national mood about the condition of the country and the trustworthiness of its politicians. Sir Keir and his people think the worst thing they could do would be to arouse expectations that they won’t be able to meet.

Some caution about what a Labour government will be able to do is reasonable because the Tories will leave it such a poisoned chalice to sup from. The public finances are stretched. Public services are in distress. Taxes are high. Growth is anaemic. The root source of pessimistic prognostication about Labour in government is that it will have little room for fiscal manoeuvre. That is allied with the assumption that governments are incapable of being successful reformers when money is tight. From that flows the misery-making conclusion that a Labour government will not be able to change anything of consequence.

The mistake here, and it is one which is particularly prevalent on the left, is to think that progress is entirely dependent on being able to spend lots of extra money. It is ahistorical to believe that you can’t be radical on a budget. William Gladstone led reforming Liberal governments in the 19th century. He was famous for being so parsimonious with the public finances that he was obsessed with “saving candle ends”. The Labour government of the 1960s implemented significant domestic change amid near-constant economic turmoil. Capital punishment was ended, homosexuality was decriminalised in England and Wales, theatre censorship was abolished, the laws on abortion and divorce were modernised. Being cash-strapped didn’t prevent the Labour government of the 1970s from legislating against sex discrimination and introducing statutory maternity leave.

Progress isn’t all about the state being able to open its wallet. The legacy of reforming governments is often not defined by how much money they spent, but by the enduring institutions they created and the social advances they embedded. Several of New Labour’s key reforms came at zero or trivial cost to the exchequer. A notable one was the establishment of the minimum wage. In advance of its creation, Tories attacked it as a recipe for mass unemployment. They now accept it as a fact of British life. The minimum wage has raised the incomes of millions of low-paid workers and been celebrated by some analysts as the most successful economic policy in a generation.

Another no-cost progressive cause implemented during Labour’s last period in government was the introduction of civil partnerships, the stepping stone to the legal recognition of same-sex marriage that followed. Of all the reforms of the New Labour years, banning smoking in enclosed public spaces was one of the greatest triumphs of no-cost progressivism. Fuggy pubs and fume-hazed restaurants are no more than a smelly memory. Deaths from heart disease and strokes have fallen dramatically since lighting up was banned in indoor venues. There’s a strong case that the ban has been the single biggest benefit to public health in my lifetime while saving the NHS the money that it would otherwise be spending on treating smoking-related diseases.

These examples suggest how a Starmer government can prove the naysayers wrong when they claim it will struggle to achieve anything. In its early period in office, there will be a need for quick wins to establish that Britain is under new and reforming management. Fortunately for Sir Keir and the rest of the shadow cabinet, they have plenty of opportunities to score. The House of Lords provides an easy way to demonstrate that Britain has a modernising government. The Blair government ejected the bulk of the hereditary peers from the claret-coloured benches of the Lords. The removal of the residual ones is long overdue. A Starmer government can get on with that swiftly, and putting it in the manifesto will quash any meaningful resistance from peers. There would be no cost to the taxpayer from telling the hereditaries that their time in the legislature is up. There would be a bit of a saving to the public purse because they’d no longer be claiming expenses.

It ought to be an early ambition for Sir Keir to strengthen relations with the European Union, and David Lammy, the shadow foreign secretary, suggests it will be. Closer ties with our neighbours will be popular within Labour’s ranks, and the reasoning will be understood by most voters, a large majority of whom now say they are full of Bregret. Given how abysmal the consequences of Boris Johnson’s Brexit deal have been, it should not be beyond the wit of a Labour government to agree more rational and less frictional trading arrangements with the EU. Mitigating some of the damage wreaked by Brexit should, over time, boost a Starmer government with a much-needed growth dividend.

It will very likely be a first-year priority for Labour to create Great British Energy, a new publicly owned clean power company. This will involve some set-up costs, but it will more than pay for itself if it is done right and catalyses the expansion of a profitable, job-creating, high-tech, future-facing industrial sector. The Blair government overrode Tory opposition to secure a popular goal in its early life by banning handguns. Soaring knife crime is a lethal stain on our society. It would be a quick win for a Starmer government, and one rectifying a Tory failure, to implement a comprehensive ban on the sale of zombie knives, machetes and other vicious bladed weapons.

There are many areas where valuable reforms require little or no additional public spending. These include modernising the school curriculum, using planning reform and the levers of the state to encourage house building, overhauling the regulation of water and other utilities, banning no-fault evictions and enhancing consumer protection. As a potential equivalent of the introduction of the minimum wage during the Blair years, Sir Keir’s circle points to Labour’s substantial package of measures to enhance the rights of workers and increase the responsibilities on employers to treat their staff properly. These include banning zero-hours contracts and ending the pernicious practice of “fire and rehire”. This may come with a cost to some exploitative companies, but will improve the conditions of many workers without involving a bill for the exchequer.

There’s no question that a Starmer government will be confronted with enormous challenges, but that doesn’t justify the excessive despondency of the miserabilist chorus. History shows that you don’t have to be a chequebook government to be a reforming government. Even when money is tight, Labour will have substantial opportunities to change lives in ways that matter a lot. They just have to be seized.

• Andrew Rawnsley is the Chief Political Commentator of the Observer