A communications system allowing emergency personnel at street level to talk to colleagues in Tube tunnels will not be fully operational until 2008.
Problems in communication were exposed by the blasts
A London Assembly report on the 7 July suicide bombings criticised the inadequate communications equipment which hampered rescuers in their work.
Only the British Transport Police were able to communicate underground by radio after the explosions - even though a report into the Kings Cross Underground fire 18 years ago had recommended that action was taken to improve the system.
Richard Barnes, chairman of the report committee, said urgent action was needed: "This can no longer remain in the "too hard to do" tray.
"In the 21st century, in one of the most sophisticated and technologically aware cities in the world, it is unacceptable for the emergency services to rely upon runners to gain and exchange information," he said.
However, despite the criticism it will be up to two years before a fully integrated system is in place.
London Underground is in the process of introducing a digital radio system called Connect, linking trains, stations and LU depots, and enabling digital radios known as Tetras to be used underground.
Tetra is a specialist mobile phone and walkie-talkie system used by police, military and rescue services, which is considered to be more flexible than normal cellular services.
The £2bn network will be rolled out line-by-line over the Tube network this year and in 2007, an LU spokesman said.
Tunnel rescuers could not communicate with those on the surface
The Metropolitan Police is also introducing a new Tetra-based radio system - Airwave - which will be compatible with the Connect network, but will not be in place until 2008.
Jonathan Fox, from the Association of Professional Ambulance Personnel, told BBC Radio Five Live it was "unacceptable" the ambulance service did not have an adequate hand-held radio system.
"We've been promised that we'll be having the Tetra digital radio network being actually put through to all the emergency services, but we never seem to see when that's going to happen," he said.
A London Ambulance spokeswoman said the service would have an Airwave digital radio system by 2008, but in the meantime had asked for 200 radios to be given out ahead of schedule.
In the meantime, two radios able to connect those in the tunnels with people at street level would be kept at every Tube station for the sole use of London Ambulance personnel, she told the BBC News website.
The ambulance service was also found to be "overly totally reliant" on mobile phone networks, a system found to be wanting when the mobile phone networks became congested.
A part of the mobile network near one of the four bomb sites at Aldgate station was shut down by the City of London police without any consultation with the other emergency services.
Hundreds of people were injured in the blasts
London Underground's own radio system - described as "very old" by the organisation's own managing director Tim O'Toole - also broke down during the response.
Details of what was happening at the four sites - Aldgate, Edgware Rd, Russell Square and Tavistock Square - were so vague that some hospitals were reduced to sending messengers on foot to bomb sites to get information.
Until the new Connect network is up and running, the only agency with radios able to work underground are the British Transport Police (BTP).
However the cable that allowed BTP radios to work underground at Russell Square was damaged by the blast.
But Assistant Commissioner of the Metropolitan Police, Alan Brown said he didn't believe that communications had hindered the response.
"Our radio systems worked well, there is a difficulty in relation to communicating from underground to above ground, we put some work rounds in place very quickly in relation to that.
"Certainly the views of my colleagues from the British Transport Police and ourselves was, we didn't feel that that was detrimental to our response."
Mike Brown, the Chief Operating Officer of London Underground, said millions of pounds were being spent on upgrading the communications system.
"We realise that our system is an old radio system at the moment but this investment was already under way prior to July last year, and the key thing now is to get it working properly."