The stabbing death of a teenage girl in Birmingham highlights a grim phenomenon in Great Britain – violent crimes committed not with guns, but with knives.

Birmingham police have arrested a 22-year-old man in connection with the knife murder of 16-year-old Christina Edkins Christina, who was attacked aboard a rush-hour bus in one of the city’s busiest thoroughfares.

Such killings are reported virtually every week in Britain.

A week earlier, a 16-year-old boy was fatally stabbed in Wandsworth, a borough in South London.

According to Citizens-Report UK, between 2010-11 and 2011-12, 21 out of 32 London boroughs witnessed an increase in knife crimes -- continuing a four-year upward trend. In some parts of the city, the number of such incidents spiked by more than 20 percent in just one year.

On the whole, London reported more than 14,000 knifings last year, while according to Parliament, England and Wales recorded almost 30,000 knife offenses.

A majority of knife crimes in London, perhaps as many as 60 percent, according to police statistics, are committed in the context of gang activities.

While overall crime and murder rates have been falling in the U.K. (as they are in the U.S.) – evidence suggests that a growing number of people are using knives for street robberies.

British police data indicate that in 2011, more than 15,300 robberies involving knives were recorded, up from about 14,000 the prior year. Overall, robberies climbed by 4 percent, while the number of crimes dropped by more than 4 percent.

Chief Constable Jon Murphy of the Association of Chief Police Officers (ACPO) said that while "violence against the person overall fell, a continued cause for concern was the increase in pick-pocketing, robbery and robbery with knives. This has been driven by a rise in robberies of personal property.”

The Jason Spencer Trust, a nonprofit based in the East Midlands that advocates for crime victims, said the most common weapon used in a violent crime in England and Wales is not a gun -- but a knife; with one in five muggers threatening victims with knives.

British hospitals are evidently seeing more patients who have been stabbed by knives and other shape instruments.

According to ITV, one in seven of all emergency hospital admissions for assault among youths between the ages of 13-24 involved a knife or sharp object.

Dr. Tunji Lasoye, Accidents & Emergency (A&E) consultant at King's College Hospital, London, told U.K. media outlets: "The numbers of stab victims coming into A&E have gone up. It used to be that we would see isolated cases at weekends, but now it is nearly every day of the week. And the age of the victims has gone down. We used to see people in their early 20s; now they are in their mid-teens. And 10 percent of the victims we see now are girls, which wasn't the case a few years ago."

As with guns, the British government has tried to tackle knife crime by banning certain types of weapons and imposing tougher jail sentences for their possession.

In 2009, the Violent Crime Reduction Act prohibited the sale of knives (even cutlery and kitchen knives) to anyone under 18, while many other types of knives are completely banned.

Adults caught carrying banned knives on their person can be punished by up to 4 years in prison or a fine of £5,000.

Knife crimes are more prevalent among Britain's poorer and ethnic minority communities. Labour MP David Lammy, who represents Tottenham in London, warned last year that most knife-wielding young killers come from fatherless homes.

“I have sat with too many parents, usually mothers, who have lost their children to knife crime,” he told a conference in October 2012.

“Usually the child that has committed the offence comes from a background where the father has been absent.”

However, gathering data on knife crimes has been difficult and may not be reliable largely due to the inexactitude of what exactly constitutes a “knife attack.” Confusing matters further may be the fact that criminals sometimes use knives in conjunction with other weapons to commit their deeds.

There are also concerns that when police agencies or academic organizations perform surveys on the extent of knife crimes, they use too small a sample size and often ignore speaking to youths, who tend to be disproportionately affected by such violence.

John Steele, the crime correspondent for the Daily Telegraph, wrote: “It is… unclear whether knife crime is going down or up. Available official statistics suggest it has fallen since the mid-1990s, but the Government concedes the limited figures are far from reliable.”

Yet, it is a certainty that UK has a much lower murder rate than the US, regardless of the weapon used.

In 2011, Britain recorded a homicide rate of 1.23 per 100,000 inhabitants, versus 4.8 murders per 100,000 population for the U.S.