Dozens of cops were mobilised to Caledonian Road last night after a group of men were reportedly seen brandishing knives.
Police were already on high alert after a blanket Section 60 was issued for the whole borough at 6.25pm, after "several violent incidents" that afternoon.
Rather than needing reasonable grounds for suspicion to be able to carry out stop and searches, a Section 60 - which is authorised by a senior officer - means police can stop and search anyone.
Cops - including armed officers - were called to the Barnsbury street just before 10pm, where at least 10 police vans could be seen parked up with their lights flashing.
Officers chased a man who fled onto the train tracks at Caledonian Road and Barnsbury Overground station.
One man, who was arrested for trespassing on train tracks and for possession of an offensive weapon, remains in police custody.
Justifying the Section 60, which can be issued when police believe that serious violence will take place, and it is necessary to use the power to prevent such violence, Islington police tweeted: "A number of unconnected incidents have occurred across the BCU (basic command unit) this afternoon involving minor skirmishes where weapons have been seen or intimated.
"During one incident one person has received minor injuries which are not life threatening or changing."
The Section 60 expired at 6am this morning.
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