A teenager has been convicted after waving a knife at a police officer while looking to snatch mobile phones from people. 

The 17-year-old appeared at Stratford Magistrates Court on Friday (June 9), where he was found guilty of assault, possession of an offensive weapon, and one count of threatening a person with a bladed article.

He had pleaded guilty to two counts of robbery at an earlier hearing.

PC Nick Fox, from the Met's Central East Command Unit, spotted two male youths on bicycles who were acting suspiciously and appeared to be looking for phones to snatch in Kingsland Road, Hackney, at around 9am on April 23.  

Hackney Gazette: PC Nick Fox spied two armed teens attempting to steal mobile phones from members of the public in Hackney, while he was off dutyPC Nick Fox spied two armed teens attempting to steal mobile phones from members of the public in Hackney, while he was off duty (Image: Met)

PC Fox, who was off duty at the time, shouted at them and in response one of the males produced a knife and waved it at him, Scotland Yard said.

The officer alerted local CCTV officers and the Met's robbery taskforce and response units.

He spotted the boys again who appeared to be about to target a lone female victim.

The officer shouted to alert the victim before one of the boys got off his bike and approached the officer, drawing a knife from his bag.

The youth saw a robbery taskforce officer arrive and jumped back on his bicycle, pursued by PC Fox on foot.

A woman helped officers by pushing the youth from his bicycle, allowing PC Fox to move in and detain him.

The teenager was arrested and taken into custody.

A knife and three stolen mobile phones were found.

Det Ch Supt James Conway thanked the woman saying "her action showed real courage and a selfless determination to assist the police preventing harm".

He added: "This is a fine example of bravery and excellent teamwork; an off-duty officer going above and beyond the call of duty, swiftly and ably assisted by his on-duty colleagues who rapidly responded to help the safe detention of the suspect.

"I am immensely proud of their efforts to help keep members of the public safe, but I’m not surprised. My officers and staff are out there every day, working tirelessly for Londoners.

"Then they go home, get up and do it all over again. This shows that even outside work they are putting the safety of the public first."

The youth will be sentenced at a later date.