Emergency services still lack radios for use underground, 20 years after the King's Cross train station fire led to calls for their use.
There were calls for the new system after the fire, which killed 31 and injured about 60, and the report into the 7 July bombs highlighted the issue.
An emergency services radio network for underground use is not expected to be ready until the end of 2008.
A wreath was laid at King's Cross on Sunday on behalf of London Underground.
Staff placed it at the station's memorial plaque for the victims of the fire, to mark the 20th anniversary of the tragedy.
It is thought a smoker's dropped match, which fell on to an escalator and subsequently slid beneath the staircase, started the blaze at King's Cross St Pancras station on the evening of 18 November, 1987.
The blaze reached the ticket hall and took almost six hours to put the fire out.
Recalling the scene, rail passenger Peter Gidley said he was on the mainline station concourse and saw "thick black smoke belching from all the Underground exits".
"If hell exists, it was on display that night," he said.
In February 1988, QC Desmond Fennell headed a public inquiry into the fire.
His recommendations, which led to the tightening of safety on London's Underground network, included the introduction of radios that can be used below ground level.
Sir Desmond Fennell said "it seems extraordinary" that "the Americans can communicate with a man on the moon", yet people in the UK cannot establish a radio network to "get a system going 20 yards beneath the surface".
Earlier this year O2 Airwave was awarded a contract to link the Airwave radio network used by the police and emergency services to the Tube's new digital radio system, with the aim of the system being operational on all Underground lines in 2008.
In February, when the £115m contract was announced, Mayor of London Ken Livingstone said the radio network would "bring added flexibility to the way that emergency services operate".
British Transport Police, responsible for policing the Tube network, already has radios which operate underground.
Under current working arrangements, emergency workers accompanied by a transport police officer who has a radio which works below ground, can contact those below ground level.
The limitations caused by this arrangement were made clear in a London Assembly report highlighting the emergency services' response to the 7 July London bomb attacks.
The report stated that police, fire and ambulance staff all used different radio systems and rescuers at ground level could not talk to their colleagues underground.
Richard Barnes, chairman of the committee examining the emergency service response, said it was "unacceptable" that recommendations made after the King's Cross fire had still not been implemented.
However, John Healey, minister for local government, said "many lessons" had been learned since the disaster.
"The ongoing roll-out of common radio systems across the emergency services will improve inter-service radio communications.
"The installation of a digital radio system on the London Underground will also further improve the emergency services communications across the Underground network, and this should be complete by end 2008."