Only half the ambulances available were sent to help victims of the 7/7 bombings, the inquest into the attacks heard today.
London Ambulance Service (LAS) also held back crews stationed near the scenes of the atrocities, meaning the injured had to be treated by paramedics who travelled in from outside the capital, the hearing was told.
There were 201 rostered ambulances available to LAS controllers on July 7 2005, but only 101 were deployed to the sites of the terrorist attacks on three Tube trains and a bus.
Further medical crews from outside London were sent to help the rescue effort and volunteer ambulances also assisted with treating and carrying the wounded to hospital.
The inquest has heard that some paramedics complained they were left to watch the events unfold on TV for more than an hour before being sent to help survivors.
Jason Killens, LAS's deputy director of operations, said some crews were deliberately held back in case there were further attacks.
He said: "Given the circumstances we were facing, we made a decision not to deploy all available ambulances to the incident scenes and essentially held back in reserve other assets for any future incidents which may occur.
"I believe that was the right decision on the day and if faced with a similar set of circumstances again, it is highly probable that we would hold in reserve assets to respond if further incidents take place."
Christopher Coltart, barrister for seven families of those killed in the suicide attacks, said LAS's internal debrief process had uncovered problems in deploying available crews to the King's Cross and Aldgate bombings.
"Resources very close to the scenes were not used in circumstances where vehicles were travelling in from well outside London to attend the very same scenes," he said.
"This is a theme, is it not, that appears time and again in relation to each of the bomb sites - that available local ambulance crews are not being deployed to the scene of the incident."
Mr Killens replied: "It's recognised that there were ambulance crews in the immediate vicinity of the scenes that were not deployed.
"As I say, 999 calls were still going on and it would not be appropriate to deploy every single resource in the immediate vicinity of those incidents to them.
"That said, I do accept that there were delays in activating available resources to the scenes."
Mr Coltart also highlighted LAS controllers' problems in establishing which crews were free to be sent to the bomb sites.
"You could not get a handle on who was available to be deployed and who was not," he suggested.
Mr Killens answered: "It's right to say that there was difficulty in ascertaining the status of the entire fleet."
On the day of the attacks, LAS received at least 190 emergency calls unrelated to the bombings about patients with potentially life-threatening conditions, the inquest heard.
The hearing was also told that the Government's official review of the emergency response to 7/7 incorrectly claimed that rescuers were not held up by communication problems.
The report, published in September 2006, stated: "It has been suggested that failures in the telecommunication equipment used by the emergency services led to a delay in rescuing those caught up in the attacks.
"This is not the case. Although there were difficulties, responders were on scene within minutes of receiving 999 calls."
Mr Coltart said: "To the extent that either the bereaved families or the wider public at large have previously relied upon the assertion contained within that report, I think it's open to us to confirm now, isn't it, that that's no longer accurate?"
Mr Killens answered: "I think based on the evidence we've heard, that's not an accurate reflection of what took place."
LAS issued a "completely misleading" statement to a newspaper about how well its communications systems worked on the day of the attacks, the inquest heard.
The ambulance service told the London Evening Standard in November 2005: "Radio contact between our headquarters control room and our ambulances was maintained throughout our response to the bombings."
Mr Coltart said: "Taken in isolation, Mr Killens, it's completely misleading, isn't it?"
The senior LAS manager replied: "In isolation, without other information around it, wider context, I would agree with you."
LAS executives were warned four months before the 7/7 attacks that a decision to switch from pagers to mobile phones for transmitting alerts to managers in a major incident could lead to "needless loss of life".
Keith Grimmett, of LAS's emergency planning unit, highlighted recent instances where "time-critical" text messages sent by the ambulance control room had taken hours to arrive.
He urged a return to the use of pagers to alert senior staff in the event of a disaster because they were more reliable than mobile phones.
"It is worthy of note that the threat from (Irish) Republican terrorism has risen a level whilst the informed view upon the risk of Islamic terrorism in the capital is a question of when not if," Mr Grimmett wrote in an email sent to LAS managers in March 2005.
Pagers were introduced for senior LAS staff following a recommendation in the Fennell report into the 1987 King's Cross fire, which killed 31 people, the inquest heard.
Mr Coltart pointed to the example of three senior LAS officers who between them managed the ambulance response to two of the 7/7 attacks without realising the others were very nearby.
"If they had been equipped with pagers, of course, it would have been possible, wouldn't it, to put them in touch with one another, thereby enhancing the co-ordination of the response to those various incidents," he said.
Mr Killens replied: "It could have been possible, yes. However, I think it's highly unlikely that the control room would have considered sending a message to each of those three officers saying the other two are in these locations."
London's mobile phone networks became overloaded on July 7 2005 as millions of people called friends and relatives to check they were safe.
Within a week of the attacks LAS started using pagers again, the inquest heard.
The bombings carried out in London by Mohammed Sidique Khan, 30, Shehzad Tanweer, 22, Hasib Hussain, 18, and Jermaine Lindsay, 19, were the worst single terrorist atrocity on British soil.
As well as killing themselves and 52 others, the bombers injured over 700 people.
The inquest at the Royal Courts of Justice in London was adjourned until tomorrow.Reuse content