Asked recently to reflect on his record as prime minister, Tony Blair chose the failure to tackle inequality as his greatest oversight.

NHS England chief executive Simon Stevens of course cut his political teeth and achieved his first great successes as part of the New Labour project and it would be unsurprising if he shared his former boss’ regrets.

That certainly seemed to be the case when he told last month’s NHS England board meeting that reducing health inequality must be an important part of the long term plan for the NHS promised for the service’s 70th birthday this July.

The only trouble is that when it comes to improving people’s health – including that of the poorest and other disadvantaged groups – the NHS has relatively little influence. Indeed, the NHS means that in the UK healthcare is the one domain where, in theory at least, you receive similar treatment regardless of socioeconomic status.

The nation’s affection has benefits for the NHS but is also very dangerous for it

The factors that have the greatest impact on health and health equality lie elsewhere: housing, public health services, social support and intervention, employment prospects, food and drink, and the environment.

Many are areas that have been starved of funds for nearly a decade (and, when compared to the largesse given to the NHS, for much longer than that).

Britain’s ever deepening love affair with the NHS has blinded it to the fact its health is only partially dependent on the quality of its healthcare system.

The nation’s affection has benefits for the NHS but is also very dangerous for it. The strains it now faces will never be properly dealt with inside the comfort of its own walls. The root causes are going unchecked and getting more and more intense – that demand will end up at the service’s door, and will always overcome capacity.

The NHS will also, eventually and without changes to funding patterns, gobble up so much public spending and GDP that a universal healthcare system will start to appear unaffordable.

Public health in the margins

Each winter it is the rise in respiratory diseases (not weather induced injury) that cripples much of the health and care system. Hundreds of millions are ploughed into dealing with the surge, while damp, poorly heated housing and polluted streets that aggravate COPD and asthma – bringing sufferers to emergency departments – are given little thought and less money.

In London and other major cities an epidemic of knife crime takes the lives of many children and young adults, the great majority from poorer communities. The NHS tries to save as many as possible by adopting highly innovative, and expensive, advances developed on the battlefields of Iraq and Afghanistan.

Meanwhile, in Glasgow, the problem was treated as a public health issue and, as result, spent much less money while getting better results.

There is even evidence that the focus on reducing delayed transfers of care in the NHS is impacting on the funding and effort that can be given to other perhaps more important issues, such as the collapse of the social care provision.

In England, public health has been slipping to the margins for a decade. The transfer to local government was one of the few parts of the Lansley reforms greeted with some enthusiasm.

But it has proved a disaster, coinciding with a clampdown on local authority spending that meant regular raids on the public health budget. The move also meant it was not directly championed by the one person with a track record of getting money out of the government in recent years – such as Mr Stevens.

 Public health’s transfer to local government was one of the few parts of the Lansley reforms greeted with some enthusiasm, but it has proved a disaster

Cuts to services like those for sexually transmitted diseases is increasing demand on already over-stretched GPs.

The NHS cannot be blamed for seeking the funding growth it needs. Although it should be activist for better health, it cannot be expected to overturn in the space of months a social and political culture that values equitable healthcare but not equitable health.

However, what it can do is, in negotiation with the government, prioritise how it spends the funding it has and whatever comes next.

One area where prevention, equality and access to services are particularly tightly linked is mental health. Mental illness is linked to poverty and more common among some racial groups. And people who live with mental health problems, appallingly, receive worse treatment in general, have poorer physical health, and shorter lives.

Timely access to mental health treatment is also the one area of healthcare in England where having money to seek private care makes a big difference.

Elsewhere, investing NHS funding for the benefit of long term wealth and health should mean spending on primary care, particularly in deprived and underserved areas; on technologies and techniques that better keep people healthy and prevent illness deteriorating; on interventions in determinants like housing and transport; and on means to bolster community support and social capital.

Money spent on these areas would have a much bigger impact on the nation’s health than the hundreds of millions that is likely to spent, for example, on reducing the average wait for an elective operation from the current 21 weeks down to the targeted 18.