Sadiq Khan has been urged to get a grip of the "horrendous" gang warfare epidemic in London after police in capital opened their 100th homicide investigation this year.
Violent crime in London has soared in recent months, briefly overtaking the murder rate in New York, and figures are on track to make 2018 the deadliest in a decade.
Detectives are now looking into the murder of Kaltoun Saleh, 43, who she died in hospital on Tuesday seven weeks after she was severely burnt in a flat fire in Finsbury Park.
Neil O'Brien, a Conservative MP, said: "Sadiq Khan needs to get a grip on this horrendous epidemic. London has the resources it needs, but needs political leadership, which is currently lacking."
As a result of the lawlessness in the capital, those attending Notting Hill Carnival this bank holiday weekend will have to pass through knife arches for the first time in the event's history.
Khan tweeted a Met Police press release detailing their policing plans for the carnival, calling it a "fantastic celebration of what makes London great", thanking officers for "making sure it’s safe for everyone to enjoy themselves".
Last year, 300 arrests were made at the carnival as those attending repeatedly clashed with police in what was meant to be a sombre occasion in tribute to the 72 people who lost their lives in the Grenfell Tower disaster.
Writing in The Daily Telegraph in July, former Mayor of London Boris Johnson accused his successor of an "abject failure to grip the problem" of violence in the city, calling his "pathetic performance" a failure to take responsibility for the wave of knife and gun crime.
Reacting to the homicide cases reaching 100 in London, former Home Secretary Lord Blunkett told The Daily Telegraph: "It's a tragedy that we have reached this unacceptable benchmark.
"It is regrettably part of a broader trend linked to knife crime and cuts. The withdrawal of resources has been particularly felt by the Met, because the Met has to pick up the cost of counter-terrorism as well."
London could this year surpass the 2017 tally for homicides - murder or manslaughter - of 131, but the comparative figure remains lower than in 2007 when it stood at 164.
With no sign of stemming the flow the bloodshed in London, Scotland Yard are taking no chances this weekend on the eve of more than a million people descending on west London for Notting Hill Carnival.
Some 13,000 officers will be deployed to the two-day event - around 450 more than last year and the highest number since 2011 when the carnival went ahead in the aftermath of the London riots.
It is hoped the "tried and tested" arches will put off those planning to arm themselves with knives and offensive weapons, but not everybody will be expected to pass through them, according to Scotland Yard.
A range of officers will be deployed, including those from the Metropolitan Police's newly-formed Violent Crime Task Force, undercover police, a the firearms unit and the dog unit.
Superintendent Elisabeth Chapple, Met spokeswoman on the carnival, said the metal detecting arches will be placed in the street and "people flow through them", adding: "We won't be specifically selecting people to go through them.
"They are designed to go with the crowd flow and detect any people who would think of bringing a knife to carnival."
"We understand the views of the community around the levels of youth and other violence using knives on our streets and we want to reassure them that it is safe to come to carnival.
"There has been knife crime this year, as in previous years, and we understand the community are concerned about that."
Analysis by home insurer Policy Expert revealed 108 reported incidents of theft, with each averaging a total of £293, compared to just 18 in the week leading up to the event.
Overall, 197 items were reported stolen, including 78 mobile phones, 40 incidents of cash, 32 credit or debit cards, 16 purses or wallets, and six handbags - totalling more than £30,000 in value.
As well as the pickpocketing spike, officers will also be preparing for an inevitable upsurge in violent clashes.
Over the course of the weekend last year, more than 300 arrests were made and 28 officers were injured as carnival attendees threw bottles and spat blood at them.
Supt Chapple added: "We are aware that in previous years there have been a number of incidents but compared with the number of people coming to carnival the number of incidents isn't significant, but any incident that does affect Londoners we want to provide reassurance."