Among the 17 firearms seized during a series of early-morning raids throughout south-east England were three Israeli-made Uzi machine pistols, several Smith and Wesson handguns, including a .44 Magnum, double-barrelled shotguns, rifles and other handguns.
On Sunday night, a 13-year-old girl was shot in the arm after being caught in a shoot-out between two gangs in Brixton, south London, believed to stem from drugs dealing.
Yesterday's raids, the culmination of a lengthy investigation codenamed Operation Lucy, were co-ordinated by the south-east regional crime squad. Chief Superintendent John Branscombe said police had broken an 'organised route' to supply the weapons to the criminal underworld.
Mr Branscombe said that Operation Lucy had begun last year as a result of intelligence-gathering following concern that more and more weapons were reaching the hands of drug dealers and robbers.
Although the investigation had been concentrated on one part of the country, it was possible that the network was part of a larger jigsaw. Detectives will now try to establish the origin of the weapons - many of which could have come from Eastern Europe.
Senior police officers are concerned at the potential for a flood of firearms to reach Britain as a result of a combination of the glut of disused weapons from the former Eastern Bloc forces, and the abolition of frontier controls within the European Community.
The source of the Uzis, a prohibited automatic weapon only rarely seen before in criminal hands in Britain, will be of particular concern.
Another officer on the investigation, Detective Chief Inspector Colin Spikesley, said: 'It is quite clear to anybody involved in the investigation of crime that in the last few months the number of weapons available to criminals has increased beyond recognition.
'Intelligence tells us guns are readily available. We are not talking about thousands of pounds to obtain them; we are talking about hundreds of pounds and the price is going down.'
The spread of firearms among underworld criminals is being examined by a Scotland Yard working party and a Home Office research project.
The number of offences involving firearms rose 50 per cent between 1988 and 1991 and has continued to rise since. Armed robberies have doubled in the same period.
London has also suffered a spate of crack-related shootings and killings, including several murders.
Many weapons are known to be available - to rent or buy - from underworld armourers.