Primary care groups risk recreating the inequalities of fundholding, researchers have warned.

A report from the King's Fund found significant variations in size, commissioning experience and health needs between the 66 PCGs in London. The authors say these differences create 'a real risk of perpetuating inequalities in health and healthcare'.

London's PCGs cover populations ranging from 57,000 to 234,000. The report says there are likely to be considerable variations in need between different PCG populations within the same health authority.

The PCG structure 'may have removed the two-tierism of fundholding', the report says. But HAs will need to address inequities between different groups to avoid the neediest people continuing to have least access to healthcare.

The number of fundholders represented varied from none to 93 per cent. In one HA, the percentage of the population eligible for deprivation payments varied from 0.3 to 24 per cent in different PCGs.

In a quarter of PCGs more than half the practices covered were run by single-handed GPs.

Public health registrar Shona Arora and primary care programme director Steve Gillam, who wrote the report, said HAs face the 'challenge' of preventing variations becoming 'entrenched'.

Senior managers agreed, but said there were positive signs.

Central Middlesex acute trust chief executive John Pope said the health service was 'moving from a fairly inequitable system'. He hoped the combination of health action zones, health improvement programmes and PCGs would 'solve some of the problems that have never been solved'.

Merton, Sutton and Wandsworth HA chief executive Sue Gallagher said her 'local experience' indicated 'strong support from PCGs' for the principle of equity 'throughout the development process'.

London's 'diversity' presents a particular challenge to PCGs, the report comments, with 'some of the most deprived boroughs in the country' side by side with 'pockets of great affluence'.

A separate report by the Health of Londoners Project, produced by the capital's 16 public health directors, highlights some of the inequities. It says the health service spends 'at least£280m' a year treating diseases caused by poor-quality housing such as TB, heart disease and mental health problems.

The PCG report, based on a questionnaire completed by all 16 London HAs, found that multifunds, GP commissioning groups, personal medical services pilots and total purchasing pilots had split apart into different PCGs. Eighteen out of 35 'primary care organisations' had merged with other practices to form a group and 16 had 'become disaggregated'.

Contracting for acute services 'should be relatively simple' in London, say the authors, since three-quarters of the PCGs contract with only one main provider.

Mapping Primary Care Groups in London. King's Fund. 0171-307 2591.£4.95

Housing and Health in London, Health of Londoners project. 0171-655 6778.