Illegal use of firearms rose by 20% this year compared to 2001.

The Metropolitan Police will increase its number of armed vehicles from 12 to 15, and there will be 50 more armed officers.

The force also wants to have 40 more specialist firearms officers next year.

Officers shot

The measures will be concentrated on the five worst affected boroughs - Hackney, Haringey, Lambeth, Southwark and Brent.

Police from the Territorial Support Group will also be deployed on regular patrols in those boroughs.

There is no street credibility in a sawn-off shotgun for today's criminals. In its place is almost the casual carrying of handguns, both real and imitation. Met Police Commissioner Sir John Stevens

Met Police Commissioner Sir John Stevens said that in the last few days a police officer had been shot and injured in Highbury, north London; plain clothes police had been shot at in Hackney, east London; and at 0226 GMT on Thursday two officers were fired at in Islington, north London.

Sir John also wants a minimum five-year sentence for anyone possessing firearms.

The police also say a ban is needed on the type of replica guns which are easily convertible into lethal weapons, and which are used in many shooting incidents.

This was highlighted in October when a 13-year-old boy held police at bay in Brixton, south London, by pointing a replica gun at them.

Sir John said: "There is no street credibility in a sawn-off shotgun for today's criminals.

"In its place is almost the casual carrying of handguns, both real and imitation.

But there has been some success in solving gun crime.

The clear-up rate in investigations of murders in Afro-Caribbean communities has risen to 70%.