Radios used by police on July 7 were branded "inadequate" two years before the atrocity but nothing was done to upgrade them, an inquest heard today.
The Metropolitan Police was singled out following a training exercise in September 2003 which revealed the force's limited capacity to communicate on the Underground.
But a senior officer today said he was not aware that any efforts had been made to improve the radio system ahead of the terror attacks in 2005.
The inquest has heard how all emergency services and members of London Underground took part in Operation Osiris on September 7 2003 at Bank Tube station.
They were asked to respond to a hypothetical chemical attack on the Underground and a report was later published, highlighting communication difficulties.
"Following that exercise and the debrief process, all the emergency responders were warned in terms that their radio system was inadequate for responding to a situation almost identical in many respects to that which transpired on July 7," Christopher Coltart, barrister for some of the bereaved families, told the inquest.
Addressing Chief Inspector James Strother, of the Met Police, he said: "In September 2003, the Met Police was singled out, in a way, in a debrief report from Operation Osiris, of not having any Underground capability and the difficulties which it caused during the course of that exercise were made plain, weren't they?"
He replied: "The only knowledge I have is what I have heard in court."
Asked what steps had been taken between September 2003 and July 7 2005 to equip officers with radios which worked underground, he answered: "I'm not aware of any attempts to provide any additional technical capability at all."
Responsibility for the radios ultimately lay with British Transport Police (BTP) he told the hearing.
"All I can say is that the Underground was BTP's territory and still is and we would tend to rely on them for the impetus to make improvements in communications," he said.
The inquest, at London's Royal Courts of Justice, has heard how the 7/7 rescue operation was hampered by restricted communication on the Underground system.
Those battling to save lives on bombed Tube trains struggled to pass information and requests for help back to the surface, often relying on "runners" to convey messages.
The new Airwave system was introduced after the attacks and allows police officers to use their radios on the Tube network.
London Fire Brigade uses Airwave above ground but employs an old analogue system underground.
The bombings carried out by Mohammed Sidique Khan, 30, Shehzad Tanweer, 22, Hasib Hussain, 18, and Jermaine Lindsay, 19, were the worst single terrorist atrocity on British soil.
The inquest, which is due to finish in March, was adjourned until tomorrow.