London Bridge attack and a similar one in March near the heart of Britain's democracy may have been shocking, but authorities have known for years that such incidents were coming.

Last year when Brits watched terrorists strike France, Germany, and Belgium London's police chief warned it was a case of "when, not if" the U.K. joined that list.

And yet more than 90 percent of the capital's police officers carry out their daily duties
without a gun. Most rely on other tools to keep their city safe: canisters of mace, handcuffs, batons and occasionally stun-guns.

Giving everyday police officers guns sends the wrong message to communities, so this thinking goes, and can actually cause more problems than it solves.

Government figures it's easier for police to remain unarmed if civilians do the same. Out of every 100 people in Britain, fewer than four of them owns a firearm.

In the U.S. there is more than one gun per person.

Might be the reason terrorists haven't signed up in droves to commit similar acts of terror in America -yet.

London Bridge Attack: Why Most U.K. Police Dont Carry Guns