London: The number of fatal stabbings in London this year has risen to over 50 with four more cases in a single day, but Scotland Yard on Friday said the city is not suffering an epidemic of knife crime.

One of the latest victims to die in four separate incidents in London on Thursday was aged 19 - the 20th teenager to have died violently in the capital this year.

Up to July 7, 49 people had died from stab wounds in London this year. Police were unable to provide comparative figures for last year, though between April 2007 and March 2008 there were 160 homicides, 72 of which were stabbings.

The Metropolitan police say tackling knife crime has overtaken terrorism as the number one priority and have set up a 75-strong team to target those carrying weapons.

But speaking after the latest killings, a spokesman said: "I wouldn't describe it as an epidemic."

"There is an issue with knives and that is why we have launched Operation Blunt 2," he added, referring to a Met crackdown on knives.

The spate of stabbings prompted Met chief Ian Blair to release a statement yesterday in an attempt to reassure the city's population. Detectives had made arrests in three of the four murders, he said.

Proactive operations

"I want to reassure the public that [police] are doing everything possible both in terms of thoroughly investigating each case and in continuing to carry out proactive operations to get knives off the streets," he added.

The latest 19-year-old victim died after suffering multiple stab wounds in Edmonton, north London, while two men in their 20s were killed in attacks in Leyton and Walthamstow in east London, with the fourth victim - a man in his 40s - knifed in Tottenham.

As well as probing those deaths, Scotland Yard is running a major investigation into the murders of two French students killed last week in one of the most brutal stabbings officers say they have to deal with.

Meanwhile, British police have arrested four people after a 20-year-old man died from stab wounds in London, Scotland Yard said yesterday.

The man was stabbed on Thursday in Leyton, east London, and was treated by paramedics, but died at the scene of the incident.

The four men arrested are being held at an east London police station as officers from the Homicide and Serious Crime Command investigate the man's death.

The Metropolitan Police has said knife crime was now the force's top issue.

Officers said they had searched 27,000 people, arrested more than 1,200 and seized 500 knives in London during a six-week crackdown. A 75-strong team has also been set up to target those carrying weapons.

A fifth teenager has been charged with the murder of Shakilus Townsend who was stabbed to death in south London last week, police said.

Detectives said the 16-year-old boy was due to appear before Sutton Magistrates Court later.

Townsend, 16, was found with a stab wound in the entrance to a block of flats in Thornton Heath on last Thursday. He died in hospital the same night.

London Those caught carrying knives on the streets of London should automatically be sent to prison, according to Boris Johnson.

The Mayor said there should be tougher sentences in a bid to drive down the recent spate of knife murders in the capital. His remarks after a meeting with Home Secretary Jacqui Smith on Thursday night echo those of Tory leader David Cameron, who last week said that anybody caught with a blade without reasonable excuse should face jail.

Johnson said: "I certainly think there is a case for tougher sentences and, yes, I think if you are caught carrying a knife then you should face a jail sentence." It follows complaints about the large number of knife offenders who escape with light sentences or cautions.