Concerned residents are calling for police action after a rise in the number of moped-related snatches in the past month.

Hampstead police reported three victims having their mobile phones snatched by robbers on mopeds last Monday and Tuesday in South End Road, Hampstead and Aspern Grove, Belsize Park.

They also report two motorcycles being stolen in the area in the last weeks, which were later used in snatching mobile phones.

Meanwhile alarmed victims and witnesses have shared around 40 separate incidents on several social media sites in the Hampstead, Muswell Hill and St John’s Wood areas which have happened in the last month.

Other eExamples include:

* A heavily pregnant woman having her phone snatched at a bus stop in Crouch End Hillat around 5:45pm on April 24. The gang then moved on to grab a phone from an elderly man.

* A 23-year-old woman having her headphones yanked off and mobile snatched by a moped rider driving the wrong way up a bus lane as she stood near Archway station.

* A man having his phone snatched on the zebra crossing outside Hampstead Heath station last Thursday at around 4pm.

* A girl having her phone snatched by thieves on a moped on April 22 at 8pm outside Tesco in St John’s Wood

* Gospel Oak’s prospective councillor, Henry Newman, had his phone snatched while photographing rubbish in Chetwynd Road as part of his campaign on April 10.

Muswell Hill Pc Sharon Rogers reported phone thefts in Colney Hatch Lane involving two scooters on Monday. She tweeted: “ALERT. Phone snatches in Conley Hatch Lane and N11 yesterday. 2 scooters involved, one red, one black. Please be aware of your surroundings.”

Victims have expressed frustration at their sense of powerlessness against helmeted thieves who disappear without trace as police struggle to catch them.

In Camden, March saw a 30.46 per cent rise in “theft of person” crimes on February, while Haringey saw a 20.57pc rise. In Barnet, the increase was 56.19pc and in Westminster 33.75pc.

Victim Rachael Power, 32, said she was “shocked” and left feeling vulnerable after a “horrible” moped-enabled theft near her home on March 24.

Her iPhone 6 was grabbed out of her hands as she was texting in Colney Hatch Lane – with her headphones still attached.

Police told her there was nothing they could do – with Ms Powers saying they were “frustrated” by their inability to act.

She said: “It’s becoming rife in the area. They need to come up with an alternative way of dealing with this because it’s becoming absurd.”

But Det Ch Insp Steve Heatley from the Met’s Road and Transport Command told the Ham&High police are working hard to make the streets “hostile territory” for moped-riding thieves.

He said: “It is important that the public are aware of their surroundings at all times and protect their personal property, as this crime happens in an instant. I would urge people to consider using a hands-free device to make a call and do not text or use apps by the roadside, where they are most vulnerable to snatch-theft.”

But he also added: “The Met wants to get across the fact that this crime is highly dangerous to the perpetrator and that they are putting themselves in danger.”

The crime is being tackled by two separate operations – London-wide Venice and Camden and Islington’s Attrition – and police patrol the streets daily.

They also stress that people should report a theft immediately, register phones at immobilise.com and learn their IMEI number by dialling *#06#