Commuters are facing delays after all services in and out of Euston Station were suspended at rush hour after a teenager was injured on the track in Wembley.
Police, firefighters and paramedics scrambled to Wembley Railway Station to reports of a concern for welfare at around 4.25pm.
A teenager, who police initially believed was 14 but later said is 17, was found at the scene. We await an update on his condition.
Scotland Yard initially said police were called to reports to a boy falling from a bridge but British Transport Police later clarified the incident was regarding a concern for welfare.
BTP said specialist police were responding to the incident.
All services were suspended in and out of Euston Station. Commuters were urged to travel via King's Cross and Marylebone instead.
In an update at 7pm, British Transport Police said the incident effecting Euston "has now been resolved".
Pictures taken at Euston show huge crowds of people gathering outside the station amid the disruption.
Commuters said on social media they have been left in the dark on trains after the power was turned off.
Bianca Lee, 38, is travelling from Liverpool to see Boyzone at the London Palladium and said she has been stuck for three hours.
She told the Standard: “There are people having panic attacks, and there is someone here with diabetes. We’ve been stuck on here for three hours, the toilets are blocked. It’s shocking.
“An off-duty train guard has started helping people, but we’re getting announcements every half an hour saying there will be an update in 10 minutes. It’s not good enough."
In an earlier statement, a spokesman for Network Rail said staff were dealing with a "trespass incident on the railway near Wembley Central which is affecting all trains in and out of Euston".
Metropolitan Police initially said: "Police were called to Wembley Railway Station at 4.25pm on Friday to reports of a boy injured after a fall from a bridge.
"Officers attended along with the London Fire Brigade and British Transport Police. A boy believed to be 14 years old was found injured.
"An air ambulance has also been called to the scene. Police are liaising with Network Rail and train operators to make the scene safe."
