Delays in sending ambulances to help those injured in the 7/7 bus bombing were condemned today as "totally unacceptable".
The first paramedic crew arrived at the scene within minutes of the blast, the inquest for the 52 victims of the July 7 2005 terrorist attacks on London heard.
But records show it was nearly an hour after the explosion before more ambulances were dispatched to assist with treating horrifically-wounded survivors.
London Ambulance Service (LAS) received detailed calls about the incident within minutes of suicide bomber Hasib Hussain, 18, blowing himself up on a number 30 bus in Tavistock Square at 9.47am.
However, senior LAS managers controlling the operation did not have access to this information in their command room and further ambulances were only sent to Tavistock Square at 10.42am, the inquest was told.
Christopher Coltart, barrister for some of the bereaved families, today questioned ambulance operations manager Paul Gibson about the reasons for this hold-up.
He asked: "Are you prepared to accept that the failure of central ambulance control to dispatch any ambulances to the scene for half an hour after it was made aware of the position was totally unacceptable?"
Mr Gibson replied: "I can't explain the decisions that ambulance control made because I wasn't there at the time."
A log shows that a St John Ambulance crew arrived at Tavistock Square at 10.37am, before the next LAS ambulance got there at 10.46am.
The inquest heard there were a series of other problems with the LAS response to the bus bombing, in which 13 innocent people died.
A member of the public called LAS at 9.48am and said a bus had been blown up outside the British Medical Association in Tavistock Square, adding "lots of people screaming".
Three minutes later a Metropolitan Police officer rang ambulance control and said 10 people had been injured in the blast.
But the LAS command team had gone into a special "gold suite" used for major incidents, which at the time did not give them access to the system recording these messages.
Caoilfhionn Gallagher, for some of the bereaved families, said: "Within the first five minutes, central ambulance control not only had multiple messages from the public which were very specific, giving the location and describing the incident, but also multiple messages from the Metropolitan Police Service, which weren't acted upon."
Mr Gibson said: "There were calls received into the LAS."
One paramedic said ambulance control told her to stand by at Fulham ambulance station in west London.
She and her colleagues waited there, listening to radio news reports about emerging details of the terrorist atrocities across the capital, until they were sent to Tavistock Square at 10.42am.
Another paramedic, Rachel Harris, called LAS control at 10.19am to say she was available and would "hang around" Camden Town in north London awaiting instructions.
Mr Coltart said: "There can be no suggestion, can there, Mr Gibson, that the reason why it was taking so long to get ambulances to Tavistock Square is because they were employed already dealing with the transportation of patients from other sites?"
Mr Gibson answered: "From my perspective of managing the scene, we didn't have a delay in receiving vehicles."
Another ambulance crew radioed in to control at 10.52am to say they had been sent to Kentish Town in north London but there was no incident there.
The LAS operator asked who told them to go there and said they should have been in the King's Cross/Euston area, near Tavistock Square.
Mr Coltart asked Mr Gibson: "Is this not absolutely symptomatic of what was happening that morning as a result of defective radios?"
He replied: "There appears to be a confusion of the call signs and two different vehicles being allocated the same call sign."
Some survivors of the Tavistock Square bombing were sent to Central Middlesex Hospital, some distance away in Park Royal, north west London, when LAS control had been told there were spaces at nearby University College Hospital, the inquest heard.
Mr Coltart asked: "Are you prepared to accept this, a very poor state of affairs in terms of the level of communication passing between the casualty clearing station and your receiving hospital?"
Mr Gibson said simply: "There were communication difficulties on the day."
Ms Gallagher asked if paramedics discussed obtaining more stretchers after learning that table-tops had been used to move the casualties.
Mr Gibson said: "I think the table-tops were a unique and excellent solution to the problem of emergency evacuation when we are considering a secondary device."
He added: "It's not a case of making do. It's a case of using necessity."