Doctors' requests for a helicopter landing pad on the roof of Oxford's John Radcliffe Hospital were rejected because it was too expensive, according to NHS managers.

Helen Peggs, spokesman for the Oxford Radcliffe Hospitals NHS Trust, said calls for the helicopter landing pad to be built on the seven-storey building were disregarded, because no-one would pay the £1.2m costs.

Her comments come after Oxfordshire Ambulance Service raised concerns that the site's existing helipad was so far away from the casualty unit that it was forced to deploy an ambulance to transport patients to the front door.

Managers told the Oxford health overview and scrutiny sub-committee that the situation held up other 999 calls in the county.

It meant seriously ill patients flown to the JR had to wait on the helipad until an ambulance arrived.

Speaking to the sub-committee, Ms Peggs said: "There was quite a thorough review carried out at the time about where we should put the helipad, in view of Civil Aviation Authority requirements, which were much stricter then.

"The option the clinicians wanted was building it on the roof, which would have cost more than £1m. No-one would pay for that, so it couldn't be pursued."

Ms Peggs admitted that since the helipad had been built, at the most northerly point of the Headley Way site, the number of air ambulances arriving at the hospital had increased from one a week to one every other day.

They fly in from as far away as Warwick, Bedford and the M4 corridor. As a result, the ORH trust is now reviewing the situation.

She said: "The CAA has relaxed its guidelines somewhat which could open up options for us. But it's still complicated. We have to look at planning issues, cost, neighbouring residents and clinical impact."

Last week, ambulance service chief executive John Nichols said the current helipad arrangement tied up an ambulance for 40 minutes each time an air ambulance arrived.

In a letter to the scrutiny sub-committee, he said: "There have been occasions when, as a direct result of OAS providing an ambulance to effect these transfers, we have had delays in our ability to respond to 999 emergencies within Oxfordshire. "

Ms Peggs said the review would be completed by November.