The knives will be recycled to make rods for the building trade

As part of Operation Blunt, officers gave hundreds of awareness lectures at schools, carried out searches and went on high-visibility patrols.

It led to 1,093 arrests, including 874 for knife-related crime. About 50 people were reported for selling knives to children.

The weapons are to be crushed at a recycling plant on Friday.

Melted down

They will be compressed into small pieces by a huge machine at the plant in Hitchin, Hertfordshire, which is capable of crushing eight cars in 60 seconds.

The pieces will then be melted down and made into reinforcement rods for concrete blocks in new buildings.

The process will be overseen by Deputy Assistant Commissioner Alf Hitchcock and Home Office minister Vernon Coaker.

DAC Hitchcock said: "Our recent operations and initiatives have ensured that thousands of knives have been taken off London's streets.

"Previous carriers of knives now think twice about going out armed with a blade."

In total, 8,723 knives were surrendered and 931 were seized by officers in London, while across England and Wales a total of 89,864 weapons were handed in to police stations.