The number of offences carried out by criminals using mopeds in London has increased by 30 times in five years.
Data obtained by the BBC shows a jump from 827 offences in 2012 to more than 23,000 last year.
High car insurance premiums and the boom in delivery services such as Deliveroo have increased the number of mopeds, an expert said.
Police insisted they had not lost control of moped crime but "there was more work to do".
During the period covered by the figures, more than 40% of such offences happened in just two boroughs.
A Met Police superintendent said the surge in Camden and Islington was "disappointing", but new measures were helping to reduce offending.
"Moped-enabled crime" describes offences carried out by people on mopeds or scooters, including drive-by thefts of pedestrians' phones and bags.
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Det Supt Caroline Haines, who leads the operation tackling moped crime in Camden and Islington, was asked if her team had a handle on the issue.
She said: "Yes we do, absolutely. Yes, there is a significant increase on last year overall, and that is very disappointing.
"Since January we've deployed a number of new tactics that are now starting to see dividends.
"But we're not done yet, and we're not complacent. We do understand there's a lot more work to do."
She said hotspots arose around transport hubs, where commuters and tourists alike were often distracted as they checked their mobile phones or looked up directions.
A plentiful supply of main roads leading in and out of London also provide easy escape routes for offenders.
Det Supt Haines said new tactics to tackle the issue include training more officers in pursuing offenders on mopeds, using remote-controlled spikes to puncture the tyres of suspects' bikes, and educating members of the public to be more aware of their surroundings.
She also urged moped riders to make their vehicles theft-proof, due to the number of stolen vehicles used to commit crimes.
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Kirat Nandra, 51, broke her ribs and hand and got concussion when she was hit and dragged along a pavement by two people on a moped in September 2017.
She was mugged on North Road, half a mile from Highgate Hill - the worst street in London for moped crimes.
"I didn't actually know what had happened to me. All I heard was my friend shouting my name, and I was being dragged," she said.
"I remember looking up, and realising the handles of my bag had got caught in the zip of my leather jacket. And I'd got tangled.
"It was so quick, so nobody could do anything."
Ms Nandra managed to pull herself free just before the moped swerved back on to the road in front of other traffic.
Her handbag, two phones, cash and bank cards were all taken.
The offenders, who wore dark clothes and had their faces covered, have not been caught because of a lack of evidence.
"I don't want to start pointing fingers or blaming, but something, somewhere, is going horribly wrong," Ms Nandra said.
Det Supt Haines said she was "sorry" to hear Ms Nandra's case was dropped, adding that her team was "absolutely committed" to bringing moped criminals to justice.
Ms Nandra, who describes herself as a strong and confident person, said she felt "ruined" after the attack.
"Psychologically, it's scarred me," she said.
"I'll never be the same again."
She had almost two months either off work or working part-time as she struggled with post-traumatic stress disorder (PTSD).
She still has anxiety attacks, fears going out alone and has moved away from the area.
"I'll be OK, but I'll never be back to what I was before. I'll always have that fear in the back of my head," she said.
Dr Simon Harding, a criminology expert from the University of West London, said the surge was partly due to criminal gangs using changes in public behaviour to their advantage.
The high cost of car insurance and the proliferation of food or goods delivery services such as Deliveroo meant there were more mopeds on the streets than there used to be, he said.
Stealing a moped was simple, as was plucking an expensive device out of a distracted person's hands, he added.
Dr Harding said street gangs on estates in north London were partly why this area has been so badly hit.
"We also know both Camden and Islington have a high number of small alleyways and canal paths - those are places that are very easy for people on scooters or bikes to access, but very difficult for the police to follow," he said.