READING, England -- During his training to become a British police officer, Ben Johnson recalled, an instructor told him and other recruits, "If you ever see somebody carrying a gun, turn and run away as quickly as possible."

"It was a bizarre situation," said Johnson, 34, a former police officer in Garland, Tex., and U.S. Army soldier who moved here with his British wife three years ago and became this country's first non-British police officer. He said running from trouble was exactly the opposite of what he learned as an American cop.

Now Johnson is publicly challenging one of the great traditions of law enforcement in Britain, what he calls the "old-fashioned idea of the unarmed bobby on the beat." He has written to his chief asking for permission to carry a gun, arguing that Britain is no longer safe for unarmed and under-trained police officers. He says he will resign if the chief refuses.

Johnson's case has caused a media furor here, partly because an American -- a Texan no less -- is claiming he feels less safe as a police officer in Britain than he did on the beat in the United States, which is routinely portrayed here as a gun-drunk Wild West.

But Johnson has also reignited a debate about whether more British police should carry guns in an era of terrorism and increasing violent crime. His supporters argue that British police need guns to protect themselves, but opponents suggest it would just lead to more gun crime. Some people who advocate arming more officers concede that even petty criminals might arm themselves in response.

Johnson said his decision was sealed by last month's death of unarmed officer Sharon Beshenivsky, a mother of three, killed as she responded to an alarm at a travel agency in the city of Bradford. She was the second police officer to be fatally shot in the past five years; in the same period two officers were stabbed to death and at least 44 were injured by firearms, according to government statistics.

Johnson and several police advocacy groups are calling for the arming of more officers; the government says only that about 6,000 of the 142,000 officers in England and Wales currently carry guns. Each police department has a small number of armed officers who are called to confront potentially armed suspects; patrol officers carry only handcuffs, pepper spray and a nightstick.

Home Office Minister Hazel Blears, who oversees all police matters, told the BBC recently that it was "extremely questionable" whether Britain had enough armed officers and that the issue should be "properly debated."

Metin Enver, spokesman for the Police Federation, the representative body for all British police officers, said his group wants about 10 percent of police armed -- roughly twice the current number. But, he said, a 2003 survey of the officers nationwide found that 80 percent did not want to carry a gun.

Enver said that "a few" more might prefer to be armed now, following last summer's deadly bombings of the London public transport system. But he said many don't want to carry a gun because of the "huge onus and burden" it places on officers.

Several London officers are under investigation and could face criminal charges for the fatal shooting in July of Jean Charles de Menezes, a Brazilian electrician. Police apparently mistook him for a terrorist suspect. Enver said the responsibility of carrying a gun "has to be off-putting" for many officers.

Britain has some of the world's toughest gun-control laws, and violent crime, while increasing, is still far less common than in the United States. There were 184 murders last year in London, a city of more than 7 million people, compared with 572 in New York City, which has 8 million people.

Here in Reading, a pretty university city of more than 144,000 about 45 miles west of London, Johnson said the leadership of Britain's police doesn't grasp the threat already facing officers on the street. His department here, the Thames Valley Police, had no comment on his request to carry a gun.

"The U.K. is changing rapidly, and the police have been slow to adapt," said Johnson, 6-foot-4 and razor thin, cradling his infant daughter in his lap in the dining room of his neat row house. "We should value the lives of police officers enough to properly equip them and train them to do the job -- even if that means getting rid of some old-fashioned notions."

Johnson, who used to stand ceremonial guard duty at the White House and other Washington sites as a member of the 3rd U.S. Infantry Regiment, said British police need far better training.

He said he had 36 weeks of academy training and supervised field work to become a police officer in Texas. But at Thames Valley he said he received less than half that, and most of the instruction involved how to fill out paperwork.

Johnson said British officers are instructed to retreat if they see a gun and call for backup from armed officers, but that can give suspects time to escape. He said he recently found himself in the same room with a man wanted for attempted murder and he could easily have taken the suspect by surprise and apprehended him.

But, Johnson said, because the man was believed to be armed, he was ordered not to approach him. The suspect walked away and was arrested by armed officers two days later.

"If he had gone out and committed more violent crimes in those two days," Johnson said, "I would have felt personally responsible."