Long before the modern welfare state, Victorian reformers knew that poor public health was the cause of much human misery. However, post-Thatcher, the debate about health inequality in the UK became marginalised, as the welfare consensus unravelled. Confined to the idealistic talk of liberals and egalitarians, it seemed to inhabit a world where the state could do it all, where the market held no sway.
Sir Douglas Black's seminal report on the subject was sidelined in the 1980s; in the 1990s a successor document provided by Sir Donald Acheson for the Labour government had little effect. Many believed that public health had had its day – and this in a country where life expectancy in some areas is the same now as in the 1950s.

This has never been a matter of absolutes. The last Conservative government may have been more inclined towards individual culpability, but it also recognised the concept of wider social responsibility and the need to protect the vulnerable in an unequal system.

However, it failed to find practical solutions that tackled the problem within a market-based social and economic system.

Has anything changed? In spite of long-term programmes to reduce child and pensioner poverty, New Labour has been surprisingly slow to interfere, even when state action would be relatively uncontroversial.

Like the Tories before them, New Labour's mantra of rights and responsibilities throws the onus back on the individual.

The message is no longer that the "have nots" are innocent victims of a vile economic order, but rather that their fate lies in their own hands. Where it has acted on traditional Labour principles of state intervention, a lack of follow-through has been a defining characteristic. The government's early years were characterised by projects such as health action zones, but these seem to have slipped into policy oblivion. They arrived with a fanfare, but then disappeared without a whimper.

Just recently, though, there have been signs of change. For the first time in decades, it appears that the public health debate is moving on.

The problem of childhood obesity could reverse life expectancy for the first time in more than 100 years

Just about everyone accepts what some have known all along: that this is a complex business with multifarious causes. It can only be tackled over a prolonged period with sustained intervention. It is also accepted that new forces must now be taken into account – new pressures, especially on the young, to consume the "right" products.

The financial and social costs of these lifestyles are becoming clearer. The government has concentrated for the past six years on attempting to turn round our creaking healthcare system: nevertheless, many in public health say not enough has been done on preventive health and addressing the underlying causes of morbidity and death, with the honourable exception of the tobacco advertising ban.

There are signs that this is also changing. Tackling the explosion in childhood obesity (something that most affects the poorest people) has become a government priority. According to the UK's chief medical officer, the problem could reverse life expectancy for the first time in more than 100 years.

This week the Food Standards Agency has stepped in, raising questions about junk food advertising directed at children and calling for a debate on how to get their energy intake and expenditure back into balance. Already, we are seeing a rise in type 2 diabetes among young people.

The same interest will need to be shown in tackling the epidemic in sexually transmitted diseases, helping to support more stable families and tackling drug abuse.