Former London Mayor Boris Johnson has said his successor must take responsibility for the knife crime in London.
Johnson said that Sadiq Khan had blamed "everyone out there" for the rising number of knife attacks in the capital.
He wrote in the Daily Telegraph: "It is tragic that so many young lives are lost on the sidewalks of our capital.
"But for my money there is another outrage – and that is the bitter failure of the London mayor to either get the problem under control or even take responsibility."
He added, "He [Mr Khan] blames everyone, except himself, when his primary duty is to bring the Londoners to safety. "
Mr Johnson, who recently resigned as Foreign Minister, said it was a "scandal" that London's murder rate was higher earlier this year than in New York.
Stop and search for the police "make a difference," he said, adding that it was a "grave mistake" for the Home Office to move away from them in 2015.
In June, Mr. Khan said, "Every death on our streets is a complete tragedy that devastates families, friends and communities.
"The extent of knife crime in our country, including London, is simply unacceptable.
"We do everything in town hall to fight this scourge."
He blamed government cuts for police funding, which "hit our city harder than elsewhere in the UK."
"I do not apologize for relentlessly persuading the government to understand that cuts have consequences and that our police service urgently needs more resources."
The number of knife and sharp instrumental offenses rose in London from 13,341 to 14,159 between 2010-11, when Johnson was mayor.
Then, in three consecutive years, the number dropped to 9,680 in 2014-15.
In May 2016, Mr. Johnson left office and was replaced by Mr. Khan.
The following year, the National Statistics Bureau recorded an increase to 12,061 crimes in 2016/17 and 14,695 next year.