There has been a massive increase in the number of mobile phones being snatched in the street in London, latest figures show.
Cases of "snatch theft," usually by teenagers and often in broad daylight, soared by 70% in the last year, with young professionals the most common victims.
Police admit it is difficult to track down the perpetrators and only a relatively small number have been prosecuted.
Earlier this year, The Metropolitan Police launched a hard-hitting campaign, warning people to be vigilant with their valuables.
It said 314 phones were stolen every day in the capital. This figure includes all crimes in which a mobile phone was stolen.
Police say young professionals out and about in public places were the most likely victims.
Figures obtained by the Huffington Post UK relate specifically to "snatch thefts," which do not involve violence.
In the most recent year available, 10,663 offences were reported - up from 6,129 the year before, and three times the 2009 total.
But in the same year, just 443 prosecutions were launched for the crime.
A Met spokesman said a small number of offenders could account for multiple snatch thefts, and admitted it was tricky tracking them down.
"I'm not going to pretend this is not a problem, it's quite hard to bring people to justice for every offence," he said.
Those who were caught were overwhelmingly male and aged under 19.
Launching the campaign in January, Detective Chief Superintendent Simon Letchford said: "Having your personal possessions on show gives robbers a chance to make easy money.
"Just being conscious of where you are and being careful about when you display your valuables can help you avoid being targeted."