The Metropolitan Police's newly appointed lead on phone theft says its work in tackling the crime has not been "good enough".
Just over 1% of phone thefts in London result in a charge or conviction, according to the force's data, compared with 11% for robberies.
London Assembly member Neil Garratt urged more to be done to tackle the issue of phone theft, which he compared to an "epidemic" in the city.
Appointed two months ago to focus on phone theft at the Met, Cdr Andy Featherstone said the force's revised strategy, which involves targeting organised crime, was making a difference.
Cdr Featherstone said the issue of phone thefts had been an "outlier" for the Met.
"But the bottom line is that isn't good enough," he said. "The public deserve better."
Earlier this month the force made 18 arrests and seized 2,000 handsets in what the Met claimed to be the UK's largest-ever operation targeting phone thefts.
"We think they are responsible for approximately 40% of all phone thefts in London," Cdr Featherstone said.
"Our serious crime directorate has been involved in these operations, which they wouldn't normally be. They would normally be involved in firearms offences, drug importation, et cetera."
He said the involvement of the directorate signalled how "seriously" phone theft was now being taken, adding: "We're putting our very best resources and assets pointed at this crime type."
Christian D'ippolito was in Hackney when he had his phone stolen by a group of four men while it was unlocked.
"I couldn't believe it," Mr D'ippolito said. "I could not believe that had just happened.
"You see, never in a million years did I expect this to happen to me," said Mr D'ippolito, who is founder of the Spartan Project, a charity supporting vulnerable young people.
He said his digital wallet, PayPal account and business banking details were compromised and the thieves even tried to take out loans in his name.
"It's quite incredible, actually, to see how, when given the opportunity, individuals can literally clear you out for everything you have in a very relentless way," he said.
He lost tens of thousands of pounds as a result.
Mr D'ippolito added: "The general public tends to view phone theft as the loss of a valuable piece of hardware, whereas the criminal mind would take that for granted and view what lies beyond the value of the phone as the real opportunity."
The Met Police said organised crime groups have pivoted to dealing in stolen phones because of how lucrative it can be.
The force said a phone-snatcher could make up to £400 per stolen phone, with devices fetching up to £4,000 when sold in China, given they are internet-enabled and therefore attractive to those trying to bypass censorship.
According to Met Police figures, 117,211 phones were stolen during 2024, up 25% on the 2019 figure of 91,481.
Neil Garratt, who represents Croydon and Sutton on the London Assembly, has repeatedly called for more action to deal with the rising numbers of mobile phone thefts in the city.
"I challenged the mayor (Sir Sadiq Khan) to show leadership last year, but he refused," Mr Garratt, a Conservative group member, said.
"So I produced a report showing how to tackle phone theft without breaking the bank."
That report, published in February, recommended targeting a "small group" of criminals which was "committing the most crime".
"News that more will be done by the Met is extremely welcome," Mr Garratt told the BBC. "But I am disappointed that the mayor has yet to take political leadership on this issue and has abdicated responsibility to an overstretched and underfunded police force.
"If Khan had pulled his finger out, how many thousands of phones may have not been stolen since?"
In response, a spokesperson for Sir Sadiq said: "Nothing is more important to the mayor than keeping Londoners safe and Sadiq is supporting the Met to double down on every level of mobile phone crime, with operations to tackle street robbers as well as the handlers and organised criminal groups driving criminality in our communities.
"Last month the mayor backed the biggest-ever Met campaign to tackle mobile phone crime, successfully disrupting an international major criminal network linked to 40% of all phones stolen in London.
"This work is happening in tandem with record funding from City Hall boosting visible neighbourhood policing and deploying specialist operations in hotspot areas like Westminster and the West End.
"But the police can't defeat this on their own.
"The mayor has long been clear we need decisive and co-ordinated action to halt the global trade of stolen phones and he will continue to push the mobile phone industry to go much further in preventing stolen phones being used, sold and repurposed, to build a safer London for all."