In a stark warning about the growing gap between the rich and poor, Sir Donald Acheson, a former government chief medical officer, says that it is now almost impossible for many of the poorest people to obtain cheap, varied food. Local shops have closed down because of the growth in out- of-town supermarkets, leading to the creation of "food deserts" in the inner cities and increasing poor nutrition, putting mothers and children at risk.
Sir Donald was appointed last year by Frank Dobson, the Secretary of State for Health, to examine what could be done to reduce health inequalities, which worsened during the 17 years of Tory rule. His report, which contains 39 recommendations, is due to be published next month and will say that priority must be given to improving the nutrition of mothers.
In a speech to be delivered to the Royal College of Physicians tonight, Sir Donald says that "poverty is unquestionably associated with increased mortality and poorer health". Research shows that a woman's diet during pregnancy affects the weight of her baby, and babies with a low birth weight are at greater risk of heart disease and diabetes in later life.
"On the basis of these findings we have concluded that while there are many interventions which will reduce inequalities between adults, those with the best chance of reducing future inequalities relate to children, to parents and in particular to present and future mothers."
Later in the speech, the first he has given about the inquiry, Sir Donald says that the food gap between the rich, who eat more fruit and vegetables, and the poor, who eat more salt and fat, parallels the health gap. "Nutrition plays a fundamental role in a range of important diseases, including some cancers, heart disease and stroke, osteoporosis ... anaemia, and obesity."
Because of its fundamental role in the growth and development of children, the plight of poor mothers is of particular concern, he says. "An extreme effect of lack of money is hunger. Hunger is prevalent in some groups today, particularly single mothers."
Sir Donald was asked by Mr Dobson to produce an updated version of the Black report shortly after the election last year, setting out the scientific case for tackling health inequalities and recommending priorities for action.
The original Black report, commissioned by the last Labour government from consultant physician Sir Douglas Black and published in 1980, controversially linked deprivation with ill health and made a series of costly recommendations for alleviating poverty, improving housing and targeting National Health Service resources at the most needy. The Conservative government that inherited it promptly buried it.
Mr Dobson is reputed to have arrived in the Department of Health in May 1997 clutching a well-thumbed copy of the Black report and in speeches last year ministers repeatedly declared their determination to reduce inequalities, promote social justice and restore fairness.
Whether these promises turn to dust will depend on the practicality and affordability of Sir Donald's recommendations. He is known to have been keen to avoid what he saw as his predecessor's mistake - disregard for cost. The Black report's proposals were priced at pounds 2bn in 1979, equivalent to pounds 5.4bn today.
Ministers have already signalled action to deal with food deserts on inner-city housing estates under the social exclusion initiative launched by Tony Blair last month. Eighteen task forces have been set up, including one headed by Tessa Jowell, the Health minister, which will examine ways to support shops in poor areas.
While not revealing the key recommendations of his inquiry, Sir Donald says in his speech that he was surprised to "live to see the day when a government was once again prepared to confront this issue". But he tempers expectations by adding that "at the very least a new inquiry might bring the issues back centre-stage for further debate".
In Britain, the political sensitivities stirred up by the issue have been extreme, he says, and he criticises the reactions of politicians which "have sometimes bordered on the ridiculous". As an example he cites the attempt by the 1979 Tory government to suppress the Black report by printing only a few cyclostyled copies which are now historical curiosities.
Latest figures show that over the last 20 years the gap in the life expectancy of those at the top and bottom of the social scale has widened. Death rates have fallen 40 per cent among social classes one and two, by 30 per cent among classes three and four, and by only 10 per cent in class five. Men in social classes one and two live on average five years longer than those in classes four and five, and women live three years longer. Illness is also greater among the poor: one in five professional men aged 45-64 have long-standing illness compared to almost half of unskilled men.
Efforts to reduce inequalities can have the effect of widening them because the better-off respond more to health and social welfare campaigns.
Sir Donald says that all social policies that have an impact on health should be subject to a "health-inequality impact assessment" to ensure that they will close the gap rather than widen it. The 39 recommendations in the report focus on 12 areas: poverty, income tax and benefits; education; employment; housing; transport and pollution; nutrition; the NHS; mothers and families; adults of working age; older people; gender and ethnicity.