Sir John Stevens unveiled the weapons seized
Metropolitan Police Commissioner, Sir John Stevens, placed the guns into a special Euroshear machine, which crushes and chops them into tiny, unusable pieces.
On average more than 600 firearms a year are seized in pre-planned and reactive policing operations in the capital.
Mr Stevens said: "By removing and destroying weapons from the streets we can continue to target armed criminals and reduce the threat of gun crime across the capital making it a safer place for Londoners."
The first weapon to be crushed was an Israeli-made Uzi sub-machine gun, capable of firing 750 rounds a minute.
Mr Stevens said: "This is a massively deadly weapon which was taken off someone on the streets of London."
The crushing machine can destroy up to 50 guns an hour and is the first of its type in the world.
'Armed and dangerous'
It is used by several other forces as well as the Met and allows weapons to be destroyed on site, avoiding the potentially dangerous process of transporting them to a specialist location.
There has been an increase of more than 100% in the number of murders involving firearms and an 11% increase in over all gun crime this year.
Mr Stevens said: "The vast majority of our police officers in London are unarmed yet they are regularly facing armed and dangerous criminals.
"The facts and figures are pretty grim but we have to face them - the good news is we are tackling this gun menace head on and we are getting results."