Police are calling for sweeping changes to European gun laws.
The Greater Manchester force says half of the weapons its officers have seized this year can be bought easily over the counter, and without a licence in many countries.
The BBC's Ten O'Clock News went undercover in Prague to find out how easy it is to obtain a weapon.
We went to the Czech capital to find out if we could buy a gun and found it shockingly easy.
We sent an undercover reporter, posing as a London businessman, to make contact with illegal gun dealers in the organised crime underworld.
Within three days, two separate gangs had offered him up to eight handguns, at about £550 each.
At that point, unwilling to break Czech law, we pulled out.
But we found that you don't have to break the law to buy a weapon that can quickly be made lethal.
We went to a high street gun shop.
Without a licence, and without proof of identity, you can buy a replica pistol, designed to fire blanks or gas pellets.
In a standard engineering workshop these can be converted to fire real bullets.
Possession of these weapons - even unconverted - can get you five years in prison in Britain.
In the Czech Republic you can buy them over the counter. They can then be mailed back to the UK, or carried by hand across the Channel by ferry.
We spoke to a member of one criminal gang who told us he had been carrying a gun since he was 18. He also sold guns.
Gun related deaths in England and Wales neared 60 in 2006-07
He said guns had become an essential accessory.
If other gangs in your neighbourhood have guns, he said, then they have to know that you are also carrying a weapon.
It had, he said, become easy to buy a weapon.
"It's common stuff," he said. "Everyone's got guns."
Young kids have guns as a fashion statement, he added.
"Like everyone wants a phone, everyone wants a gun."
He said it was for protection.
"If you're in a gang and you see members of other gangs then obviously you need it - before they shoot you, you have to shoot them."
I asked him how easy it was to buy a gun.
"It's like walking into a shop and asking for a chocolate bar," he said.
This year, Greater Manchester Police have seized more than 400 illegal weapons.
Half of them are of the type we bought legally in Prague and returned to the shop - replicas that are then converted.
Det Insp John Lyons showed me an example of a gun, seized from the streets, that had been converted from a replica.
It had been recovered along with a silencer. An assassination kit, DI Lyons called it.
Greater Manchester Police say they now want Europe-wide legislation to regulate the supply and sale of replica guns. DI Lyons said replica guns were on sale lawfully in the Czech Republic, Germany and other countries without any regulation at all.
"You go in, you hand over your money, you walk out with one of these or two of these, or as many as you can afford to buy," he said.
"You don't need a licence. You don't need to prove who you are so we'd like to see them banned.
"But we recognise that that is probably an unobtainable objective at the moment, so what we want to see is this piece of legislation including regulations around these convertible weapons as a start.
"That will inevitably have a positive impact on the number of weapons that we find on the streets of the UK."
A Home Office spokesman said the sort of "readily convertible" replicas featured in the report were already prohibited in the UK.
"We have been working with the European Commission to amend the definition of firearms in the European Weapons Directive to ensure that stricter controls in other Member States will apply," he said.
"It is an offence to convert an imitation into a firearm and anybody in possession of a prohibited firearm faces a minimum sentence of 5 years and a maximum of 10 years.
"ACPO has a control strategy in place which encompasses the reduction in the supply of firearms both into and within UK, through working in partnership with agencies such as SOCA and HMRC, who have a major role to play in identifying and controlling vulnerable points of entry."