The Metropolitan Police is considering deploying armed officers on foot patrols to prevent violence in areas “where gang activity is likely”.
Met Commissioner Cressida Dick told a hearing the move would only be used in “extreme circumstances”.
In a memo seen by the BBC, she said the measure would only be used for “short periods of time”.
The Met said armed patrols would not be “routine”, but a Labour peer warned they would be “seen as provocative”.
The number of violent deaths in London has reached 127 so far, surpassing 2017’s total of 116 killings.
In the memo seen by the BBC, email recipients were told the idea of armed police on foot patrol was part of a “recent internal discussion” into how to reduce violent deaths in the capital.
If adopted, the armed patrols would be “based on an informed and reliable intelligence picture of where gang activity is likely”, only be done in “full consultation with the local policing borough” and be used as a “temporary measure for short periods of time”, the memo stated.
Ms Dick told a London Assembly hearing the change would only be “half a step on” from the status quo and represent a “small change in tactic in extreme circumstances”.
Met assistant commissioner Sir Stephen House told the same hearing the armed patrols were part of a “range of tactics” the force was considering to “get ahead of the violence”, and added the force was at “very early stages” of a “very limited consultation”.
In a later statement, he said: “We are not considering routine deployments of armed officers in our communities.
“As part of our response to the increase in violent crime in London we are examining how our armed officers can provide extra support and augment other units, either in response to a serious assault, or to be deployed to areas where we have intelligence that serious violence is imminent.
“Any deployments would be for a limited time only and done in consultation with local policing commanders, and after a community impact assessment had been carried out.”
The Met confirmed it had contacted a community group for “initial views” on how communities might be impacted by such activity, but had not yet made a decision.
But Labour peer Lord Harris told the House of Lords he was “not convinced” the move would be helpful.
He added: “It would be seen as provocative, it will inspire fear rather than reassurance, it will hinder community confidence and do little in itself to reduce the number of violent incidents.”
Ms Dick told the hearing she and her colleagues were “hugely aware” of the “sensitivity there has been over changes to the disposition of armed officers”.