A number of home-made weapons have been handed to police

But, as an educational weapon, it can only be a good thing, he added.

The national five week amnesty ended on Friday.

In the West Midlands at least 8,570 bladed weapons have been handed in - the vast majority coming from Birmingham, the Black Country and Coventry.

Despite this, eight serious or fatal stabbing attacks took place in Birmingham during the knife amnesty period.

Number of weapons handed in across the forces West Midlands - 5,000 Staffordshire - 1,500 Warwickshire - 570 West Mercia - 1,500

Prof Douglas Sharp, a criminal justice expert at Birmingham's University of Central England, said: "Somebody who is carrying a knife because they are actively involved in crime or because they fear they will be a victim of crime is not going to hand their knife in.

"But this amnesty does provide an educational need and it does remove weapons that could fall into the wrong people's hands so it can only be a good thing.

"But, it is not going to stop people from stabbing each other."

'Young are frightened'

Most young people who carry knives around with them are doing it because they are frightened, he continued.

"My suspicion is there has always been a lot of knife crime. Young men have always carried them.

"The government has made many attempts to prevent it. In the 1960s and 70s they made the selling of flick knives illegal, for example.

"But there is no evidence that actually suggests the use of knives is more significant now than it used to be."

We don't want a knife to be something people pick up before they go out, like a wallet or mobile phone Supt Gordon Scobbie

The situation is that people are more aware of it and it may be that the number of crimes seems to be going up because more incidents are being reported, he said.

"The fact is young people do not realise how dangerous these weapons are. They need to be educated about that.

"But anyone who thinks it (the knife amnesty) will stop serious crime is deluding themselves."

'Beneficial effect'

Supt Gordon Scobbie, of West Midlands Police, is in charge of rolling out this education across the area.

And he thinks the knife amnesty has already had a beneficial effect.

"Handing in weapons is only part of a longer term strategy. Education is the other part. We are targeting 11-16-year-olds and getting them to engage in meaningful dialogue."

Police have been asking people to walk through metal detectors

The scheme has already had a success when a year 12 pupil, taking part in a school debate, stood up, removed a knife from his bag and handed it in.

"Potentially, that action has saved a life.

"We know these amnesties are not going to change things overnight.

"We don't want a knife to be something people pick up before they go out, like a wallet or mobile phone."

In Coventry, police have put up walk-through metal detectors in the city centre on weekend nights in a bid to get the message through.

"We have to put up as many barriers to people who carry knives as we can.

"Even though people will continue to carry them we have to make it as uncomfortable as possible.