Police crackdowns on the possession of firearms has led to an increase in the use of converted imitation weapons, a study has concluded.
Gun crime is linked to the drugs trade, a study finds
The survey found that specialist criminal "armourers" are supplying weapons through a close-knit network.
The research team has called on the government to do more to prevent the conversion of imitation weapons.
Home Office minister Tony McNulty said new laws were being introduced banning the sale of imitation firearms.
A total of 80 criminals aged 18 to 30 and convicted under the Firearms Act were interviewed in jail for the Home Office-commissioned study.
The research found converted imitation firearms were more widely available than purpose built weapons.
Gavin Hales, of the University of Portsmouth and a member of the study team, said: "What we have seen is a rise in the past five to ten years in the availability of converted imitation firearms.
"It reflects the fact that real guns are hard to get hold of and attempts to reduce them have worked. Why would you use an imitation when you can get a real gun?
"The offenders themselves are also wary of using such guns because of their lack of accuracy and the fact they could blow up in their hands."
The main sources of firearms were found to be illegal importation, the burglary of guns and the conversion of imitation firearms.
Specialist criminal "armourers" were mentioned by at least 12 of the interviewees.
Prices ranged from £20 for an imitation firearm, £50 for a shotgun, £1,000 and above for a purpose-built handgun and between £800 and £4,000 for an automatic firearm.
The study also found that most gun possession and use related to the illegal drugs market.
Offenders said guns were used often as a result of disputes relating to status and respect.
They said trivial disputes may result in shootings as guns elevate threat levels and a "shoot or be shot" attitude is held by many.
Many offenders told the research team that they had become involved in the use of guns after seeing the wealth achieved by community figures involved in armed robbery or drug dealing.
The study team called for a crackdown on imitation firearms but said gun crime represented a "challenge".
The report concludes: "The illegal use of firearms is not a singular problem but is complex, entrenched and poses significant challenges to communities, police and policymakers.
"Some findings point to clear recommendations, such as greater efforts to tackle the availability and conversion of highly realistic imitation firearms.
"Most, however, are more challenging and require social and economic rather than technical solutions."
Home Office minister Tony McNulty said: "We are committed to tackling gun crime through tough legislation and working with communities.
"Firearms offences fell by eight per cent in the 12 month period up to June 2006 and we want to drive it down further.
"Through the Violent Crime Reduction Act 2006 we will be introducing new laws to ban the sale, manufacture and importation of realistic imitation firearms and a new offence of 'minding' a firearm.
"This new legislation builds on the mandatory five year sentence for possession of a prohibited firearm and, in fact, extends this sentence to other possession offences."