Managers have appealed to prime minister Tony Blair for action to halt a 'crisis' in intensive care in London.
A letter from 33 intensive care unit managers says 'patient safety is being compromised' by severe nursing and bed shortages.
The appeal was made as Nigel Crisp, director of the new London regional office, launched a report detailing improvements in the capital's health services a year after the Turnberg review.
The South Thames Intensive Care Unit Managers Group claims that critically ill patients have been exposed to 'substantial risk' by an 'unacceptable level of transfers' between hospitals.
In a letter the group says some patients 'have been transferred up to four times during their period of intensive care' because of bed shortages.
Group chair Eddie Crunden said members - now based across London and the South East region - had been forced to approach
Mr Blair because 'a very selective picture is painted' by health authorities that 'don't understand' intensive care.
'We felt it was important he should hear from the people who deal with it on a day to day basis,' he said.
Mr Crisp said a group had been set up to look at transfers of 'the most severely injured' patients.
He said it would draw up protocols so trauma patients reached 'the right hospital first time', and create a 'safe system' for transfers.
Last week, 25 per cent of London's hospitals had spare beds in intensive care 'so generally there is capacity in the system', Mr Crisp added.
Mr Crunden said his members 'are not confident that the new London region will tackle the problems' and intensive care had been 'neglected', even though it underpinned other acute services.
The incoming Labour government commissioned Sir Leslie Turnberg, a former president of the Royal College of Physicians, to carry out a comprehensive review of London's health services.
It was instrumental in 'saving' St Bartholomew's Hospital as a specialist centre for cardiac and cancer care, but painted a gloomy picture of poor primary care and mental health services.
Mr Crisp said progress included a£1.2bn building programme covering 17 London hospitals and an 18 per cent reduction in the number of sub- standard GP surgeries. He said this was 'a good start in this first year'.