A man has been arrested after a small blast at a London Underground station last night believed to have been caused by a faulty drill battery, British Transport Police said.
The 23-year-old, from Enfield, north London, was held on suspicion of doing an act likely to cause an explosion to injure or damage property, and endangering safety on the railway.
He has been released under investigation pending further inquiries.
Five people suffered minor injuries after the explosion at Southgate Tube station, BTP said.
Officers were called to reports of an incident shortly after 7pm.
London Ambulance Service said two people were taken to hospital and three others were treated at the scene.
London Mayor Sadiq Khan praised the emergency services for "a swift and professional response" to the incident.
BTP confirmed the incident was not believed to be terror-related.