A Met Police report has branded knife amnesties as a waste of time.

A report showed that after an eight week amnesty over the summer - known as Operation Blunt - the number of knife crimes returned to normal levels within weeks.

Croydon Police took part in the amnesty and launched its own earlier in the year. But there are fears the police initiatives are not having enough effect and that more needs to be done to tackle what is becoming a growing concern for law-abiding residents.

In February the Croydon knife amnesty was launched by Anita Brown, the mother of Gavin Brown, who was stabbed to death in Parkfields, Shirley, last year.

By the end of March 140 knives had been handed in but knife crime, stabbings and murders continue to occur regularly in Croydon.

In May Tracey Ann Meade, a 39-year-old welfare assistant was found stabbed to death near garages in Warminster Road, South Norwood.

In the same month two men were stabbed in separate horrific incidents at railway stations in the borough. One victim had to have part of his liver removed following an attack at Thornton Heath railway station, while a 40-year-old Croydon resident suffered a collapsed lung when he was stabbed at Norbury railway station.

At the end of the Met's eight week operation in July knife crime rates in London dropped from 34.9 a day to 31. But the figure went back to 34.2 a day within six weeks of the amnesty ending.

In September - just two months after a nationwide amnesty ended - there were two knife attacks on Croydon trams and a gang attack on a 17-year-old who was stabbed in the Whitgift Shopping Centre.

Last month 16-year-old Eugene Attram was stabbed to death during a savage street brawl between 30 youths in Mitcham.

Eugene's father, Mack Attram, made an emotional appeal to get knives off our streets following his son's murder.

He said: "We're not looking for revenge, we're looking for justice - to stop these stabbings on the streets of London."

A spokesman for the Met said knife amnesties had a limited effect on tackling knife crime unless they were used in conjunction with other initiatives.

Croydon police Borough Commander, Chief Superintendent Mark Gore, said: "Knife amnesties assist by raising the awareness in the local community of the dangers of knife crime.

"A large number of knives were surrendered during the amnesty but the real focus of the amnesty was to raise awareness of the dangers of carrying knives."

Councillor Steve O'Connell, joint deputy leader and cabinet member for crime reduction and public protection, said amnesties were a "positive step".

He added: "We go into these events with optimism but also a sense of realism. Croydon won't be cleansed of knives overnight just because another amnesty is taking place.

"But any activity that helps raise awareness of the dangers associated with carrying knives can assist in the overall objective of trying to make Croydon a safer place.

"Other steps are needed - including an education drive to convince youngsters especially that carrying weapons puts them at greater risk of being injured themselves.

"This kind of education should start in the home, as children learn the difference between right and wrong."