A man was being held by detectives today after an arson attack on a police station.
The fire, started in the early hours, caused damage to the ground floor at Walthamstow police station in north-east London.
A man in his 30s was arrested outside the building, which was empty at the time of the blaze, Scotland Yard said.
"When units arrived at scene they realised smoke was coming from the building and there was a small fire inside," a spokesman said.
"A man, aged in his 30s, was arrested outside the station on suspicion of arson. He is in custody at an east London police station."
The ground floor - which suffered smoke damage - has been made safe by London Fire Brigade but the front counter service will be closed all day.