Outer London hospitals, which serve two thirds of the capital's population, are on a 'hit list' for sweeping cuts, according to claims by the health service union Unison and the pressure group London Health Emergency.

Casualty units could be under threat in 12 hospitals, seven in outer London, according to a report published yesterday into London's 'twilight zone' - the suburbs. According to the report, Rings of Crisis, the accident and emergency units most likely to face pressure to close include:

Oldchurch hospital in Romford;

Chase Farm and North Middlesex in Enfield, which are likely to offer a casualty service on only one site;

Edgware General Hospital;

Mount Vernon and Watford hospital casualty units, which are likely to merge;

Central Middlesex Hospital, Park Royal;

West Middlesex or Ealing general hospitals;

Queen Mary's Hospital, Roehampton.

The report's authors, John Lister and Geoff Martin, base their claims on the money likely to be available to health authorities over the next five years.

They argue that, under the new funding arrangements, pounds 118.6m will be lost. As part of the new internal market in the NHS, health authorities are given a budget, based on the size of the local population. They buy in services from local hospitals under an annual contract.

The hospitals are forced to compete to provide the best and cheapest contracts to stay in business.

Godfry Eastwood, London head of health for Unison, said there was no long-term strategy behind the plans to close accident and emergency departments, but that health authorities were being forced to take piecemeal decisons. 'It's a recipe for chaos,' he said.

Unison and London Health Emergency have written to the new health minister, Gerry Malone, asking him to put a stop to existing closure plans, invest an extra pounds 50m in the capital's health services and appoint a London-wide health authority which would draw up a strategic plan for health services.

Last year, the Government had to step in with extra cash after University College Hospital faced closure when its purchasing health authority, Camden and Islington, decided it could buy operations more cheaply elsewhere.

The Department of Health yesterday said the allocation of funding in London was under review.

The Government had committed pounds 200m transitional funding in the past two years to hospitals to smooth the shift to an internal market. A spokesman said a further pounds 120m had been invested to improve GP services.