"Some children will either be dead or brain damaged by the time they reach the hospital, " Dr Sean J Fennell told the Sunday Tribune.

"If you have a seriously premature baby, or a child with a serious head injury, you really need tertiary care and you need it fast.

"The longer it takes to transport the child to the new hospital, the more damage will be done. Some of the children I have accompanied to hospital in the past would have been dead if we hadn't had a helicopter. It is absolutely essential."

The hospital cannot have a helipad because of its proximity to Mountjoy prison. It is the latest problem to emerge since health services boss Professor Brendan Drumm controversially decided to locate the new national children's hospital at the Mater site . . . in Taoiseach Bertie Ahern's constituency Fennell has worked in hospitals throughout the US, Canada and Germany, and said that the decision on the Mater site . . . backed by the Health Service Executive (HSE) and approved by the cabinet last week . . . should be reversed if helicopter access cannot be guaranteed.

"It's a basic service of any modern hospital, especially one serving the entire country, " he said.

"It's like suggesting a hospital without electricity, or locks on the doors. It's just stupid."

A storm of criticism has followed the Mater decision with opposition parties accusing Drumm of succumbing to political pressure.

Fine Gael health spokesman Liam Twomey said that transporting patients by helicopter was the future of medicine, and that a helipad was a crucial service for the new hospital.

"There shouldn't be any politics in this, " he said. "Being able to build a hospital quickly cannot be the biggest priority. I want to see justification for the process. We abolished the health boards to get politics out of health. If it now turns out that politics is still playing a part in such huge decisions as this, then we must question the role of the HSE."

Drumm has publicly denied that there was any political influence.

Since Drumm's appointment 10 months ago as CEO of the HSE, the health service has been plagued with controversy, with Liam Doran general secretary of the Irish Nurses' Organisation this weekend telling the Sunday Tribune that "no one knows who's in charge".

Two of Dublin's hospitals have also expressed serious concern. In a letter to the Minister for Health, Crumlin hospital said the decision was based on "an incomplete and superficial analysis of only some of the criteria set out in the McKinsey Report".