Now, CBS News Correspondent Richard Roth reports, there's an upshot no one predicted.
Police say that since handguns have been outlawed, outlaws have taken up replicas from realistic-looking toys to expensive scale models. British police estimate that four out of five gun crimes in Great Britain are committed with these fakes, which are easily bought in stores or over the Internet.
Where the trade in replica guns is booming, and legal, the government wants it stopped.
"I think controls around manufacture, controls around sale, and certainly controls around possession in a public place ought to be the way forward," said Assistant Commissioner James Hart of the City of London Police Department.
Authorities say it will be difficult writing a law so that replica guns can still be legal for use in movies or theater, but that's a technical problem here, not a political obstacle.
The government says it won't take water pistols out of the hands of British children, but advocates of gun control in Great Britain have already proved their political clout and now they have a new target. If a replica's realistic enough to frighten someone, they say, it ought to be illegal.