It comes as London had its deadliest year for teen murders in a decade, with 28 teenagers killed in the city in 2021 so far.
At a Q&A session with Sadiq Khan on policing and crime in the capital, the commissioner rejected the target, and said the Met had a “fantastic” 97% detection rate for murder.
Caroline Russell, Green Party assembly member, asked Dame Cressida: “Would you consider adopting a target to reduce murders to zero in London in 10 years?”
In response, the commissioner said: “Frankly I don’t think I would.”
She highlighted the Met’s “97% detection rate for murder” and said: “We’ve had some fantastic successes.”
But she stressed that while the total murder figures for 2021 are not yet known, in 2020 there were “around 140” murders in the capital.
“To go from 140 to zero in 10 years,” Dame Cressida said.
“I would be keen to aim towards it but I don’t believe in targets that we’re not going to achieve.
“[It] may be longer than 2030.”
Ms Russell responded: “There is no other appropriate number for a homicide target.”
Dame Cressida has been under fire for much of the year over a string of controversies relating to the police.