Rules for buying working antique guns that are currently slacker than laws for dealing scrap metal are to be toughened up in a bid to stem criminals' access to deadly weapons.
Changes coming into force tomorrow will stop convicts being able to buy or possess old weapons, and by the end of the year dealers will have to keep computerised records for at least 20 years.
Police have long expressed concern that criminal gangs are buying and using antique guns that are still capable of firing, and getting ammunition made to fit the firearms.
These included the killers of soldier Lee Rigby - Michael Adebowale and Michael Adebolajo - who had an unloaded rusty Dutch KNIL 9.4mm revolver that was 90 years old.
Detective Chief Superintendent Gordon Allison, who leads Scotland Yard's Trident Gang Crime Command, said violent criminals are exploiting existing loopholes in the law.
Crackdowns on the importation of more modern weapons have caused criminals to resort to buying old guns, and to try to use the antique laws to avoid arrest.
He said: "We welcome these additional new controls for an area of firearms trade that until now has been unregulated. Previously the laws for dealing scrap metal have been stricter than those for dealing antique guns.
"We are not talking about converted weapons here - these sought after, collectable items are capable of firing live ammunition, and criminals, in particular gang members have exploited the loopholes in the law.
"These changes will enable police to ensure our resources are focussed on those people who do not have a genuine reason to possess these weapons and those involved in gun-related criminality."
The changes mean that anyone who has been given a suspended sentence of three months or more will no longer be able to buy or possess an antique gun or ammunition for five years.
Director of Public Prosecutions Alison Saunders has already issued new guidance to prosecutors dealing with such cases and warned that criminals will no longer be able to abuse the law.
Crime prevention minister Norman Baker said: "We are introducing a new offence of possession of a prohibited weapon or ammunition for sale or transfer, which will carry a maximum penalty of life imprisonment, and we are increasing the maximum sentence for the international trade of a weapon or ammunition from 10 years to life imprisonment.
"We are also ensuring people prohibited from possessing a firearm are banned from owning an antique firearm.
"The UK has some of the toughest gun laws in the world and I am determined to keep it that way. The trade in illegal firearms and misuse of legal firearms endangers lives, that is why we are taking extra steps to improve public safety."
As well as the changes to antique gun laws, a new offence of possession for sale or transfer of a prohibited weapon or ammunition is being created, which will carry a maximum life term.
The manufacture, sale or transfer of a prohibited weapon or ammunition will now carry a new maximum penalty of life imprisonment, as will the manufacture, sale or transfer of prohibited firearms and ammunition without authority, and their import or export.