70 years old this week, the NHS is Britain’s greatest invention and the best symbol of what we stand for as a country. It is compassion in action, care with a human face and solidarity writ large and the very idea of sharing written into the fabric of our nation.

On the morning of 5th July 1948 in what was then the Conservative city of Edinburgh in 1948, local notables heard a memorial service to mourn the passing and commemorate the contribution of the voluntary charitable and private hospitals that were being nationalised. Fifty or so miles away in Labour Glasgow, university medical students unfurled a red flag on the roof of the city’s main infirmary to celebrate a socialist advance. The Glasgow students were on the right side of history.

From the relative comfort of 2018 it is easy to forget the squalor and hardship from which the NHS released millions in 1948 — and how, at a stroke, the NHS ended the scandal of nurses having had to leave the beds of patients to run charity flag days to pay for vital equipment.

The arc of the moral universe is long, Martin Luther King said, but it bends towards justice. It does not bend of its own accord, however, and it was the 1945 Labour government that made history turn a page by making healthcare free – and free of the fear of being unable to pay.

In the final days of the Second World War, Conservative ministers in the then coalition government favoured the introduction of a paying health service. They wanted patients to pay fees for stays in hospital and decide by means-test who paid for visits to your GP.

But the Labour Party stood firm. Already Tom Johnson, the Secretary of State for Scotland, had vetoed charges for Scottish hospitals and, having built a state-run, hospital network in the north to meet war-time needs, he proposed a free peacetime NHS.

Then in 1945 Aneurin Bevan took over as health and housing minister. He refused to return our country to the dark days where doctors had to check your wallet before they checked your pulse. In mining valleys, industrial towns and cities, the strongest and bravest of men and women were in fear of going to the doctor not because of their pain – they could tolerate that kind of suffering – but because their families would be impoverished and even made destitute by the medical bills incurred.

Bevan talked of ‘taking the shame out of need’, and so he championed the implementation of a revolutionary idea. As a community, we would nationalise the hospitals, entice professional staff into working for the community, not for profit, then pool and share the costs fairly across the country. We would spread the benefits of the best medical treatment, previously denied to the poorest across our society.

So after 1945, and in the face of huge Tory opposition, Bevan took the boldest steps of all: bringing reluctant GPs on board for a public service, legislating that medical care be paid out of taxes and issuing a guarantee to anyone who was sick or infirm that their right to care would be on their needs and not on their ability to pay.

No other country had ever taken the unique and pathbreaking step Bevan ordered. And even now, 70 years on, few have dared raise the necessary taxes to follow Britain’s lead. Even in 2018, despite President Obama’s momentous healthcare reforms, millions in the USA remain uninsured and without the protection they need when they fall ill.

Exactly 15 years ago, a Labour government that I was proud to be part of found a way to refinance the NHS for the new century. With the biggest single tax rise in our country’s history – £9bn a year more from a 1p rise in employer and employee national insurance – we were able to employ 30,000 more doctors, 80,000 more nurses and start the biggest hospital building programme in NHS history.

Now in 2018, after eight Tory years of austerity, the fight for the NHS is being led by Shadow Health Secretary Jonathan Ashworth. He has said we must offer the NHS more than Mrs May’s announcement of a few days ago. We must refinance the NHS properly to meet new needs, integrate social care and health care for the elderly, and – as we had to do under Labour – eradicate the growing backlog of underinvestment, staff shortages and missed targets. We must remind the British public once more what we will lose without a fully-funded NHS.

10 years ago, I was privileged to attend a long over due service of thanks to NHS staff at Westminster Abbey as we celebrated 60 years. The most powerful speech I heard that day came from one of the NHS’s first nurses, who told us never to forget the conditions that existed before 1948.

Let us not forget what the then health minister Aneurin Bevan taught us from his experiences of the mining valleys in the interwar years: that the very existence of the NHS sends out a message that Britain is not a marketplace but a community. Here, people do not see health as a private profit-and-loss business but a public service that should be there at all times to save and improve lives.

Because of its founding principles, the British NHS is a beacon to developing nations across the world where babies die unnecessarily because of poverty, chronic illnesses remain unaddressed, the NHS vision of healthcare freed from market fundamentalism is desperately needed. It is the model of care of the British NHS that we had in mind when as a Labour government we persuaded a number of African countries to make healthcare both universal and free.

Of all the words used by Bevan to describe the benefits from the verities of the NHS, the one he returned to most often was a word we rarely use today: serenity. Even when faced with the most morale-destroying and life-threatening of illnesses, patients had the security of knowing that the NHS was always there for them when they needed it.

After decades in which great grandparents, grandparents and parents had no peace of mind when their loved ones were sick because they simply could not afford the standard of treatment needed, serenity is what the post 1948 NHS provided. It is for this reason that the achievements of that Labour government will live on forever in the memory of those whose lives it enhanced.

Gordon Brown is a former Prime Minister and Labour leader.