Current advice: Put your baby to sleep on its back

Australian researchers say that "back to sleep" campaigns have failed to have the same impact in other countries.

However, British scientists insist that the programme has saved 10,000 lives in the past decade.

Dr Peter Blair, from the University of Bristol, said that it had been a "resounding success".

The UK rate of cot death - where young babies die while asleep for no obvious reason - halved swiftly following advice that babies should be put to bed on their backs.

However, although this might suggest that asphyxiation is responsible for some of the deaths, scientists admit that physical proof of this is lacking, and a number of other theories cannot be ruled out.

Post-mortem

Research to try and establish a cause of death for cot death babies have been further hampered by sensitivities following the Alder Hey tissue theft scandal.

Research testing the response of healthy babies to non-harmful physical stresses is considered unethical by many.

In England and Wales alone, nearly 10,000 lives have been saved in the past decade, which is a testament to all who work in the sudden infant death field Dr Peter Blair, Institute of Child Health, University of Bristol

Dr Paul Goldwater, from the Women and Children's Hospital in North Adelaide, said that a recent rise in cot deaths in the state of Victoria - despite the "back to sleep" advice - raised question marks over its true role in the fall in sudden infant death.

He said that post-mortems on babies who had died suddenly had revealed certain common factors - but that not enough had been done to investigate these.

"It would appear that major clues provided by pathological findings have been largely overlooked, and as a consequence, much effort, time and money has been wasted on projects that satisfy only sub-specialty and political needs."

He suggested it was possible that "natural variation" in the rate of cot death could be responsible for the vast improvements seen around the time the new advice was introduced.

He pointed out that in Sweden, rates of sudden infant death had - despite a fall in the early 1990s - returned to the same rate as in the 1970s.

If rates rise elsewhere, he said, a "reappraisal" of the tactic might be needed.

Successful

However, his view was challenged by Dr Blair, who said that the success of the campaign was clear to see.

He said evidence of the "return" of cot death in some countries and regions was based on relatively small numbers of cases, which could be misleading.

"In England and Wales alone, nearly 10,000 lives have been saved in the past decade, which is a testament to all who work in the sudden infant death field.

"The process has been one of working out the answers without really understanding the mechanism of risk.

"Repeated population studies pointed to the prone position, and successful intervention campaigns have shown beyond doubt this position is part of the causal pathway for some of the deaths - but we have little idea as to what this pathway is."