A man has been taken to hospital after fleeing a large blaze at a block of flats in the Barbican.
Video on social media shows flames pouring out of a third-floor apartment window next to St Bartholomew’s Hospital at 4pm on Thursday.
One man left the building before the firefighters arrived and was treated by London Ambulance Service crews.
He was then taken to hospital where his condition has not been released.
A London Fire Brigade spokesman said: “Six fire engines and around 40 firefighters are tackling a flat fire on Bartholomew Close in Barbican.
“Half of a four-roomed flat on the third floor of a residential block is currently alight.
“The Brigade’s 999 Control Officers have taken more than 35 calls to the blaze.”
Clergyman Marcus Walker at nearby St Bart’s church tweeted: “A fire has broken out right next to St Bart’s. Please pray for the people of Bartholomew Close and for the emergency services who have got here in record time.”
He told the Standard: “It is lucky nothing’s hit the church - we turn 900 next week. I had [fire devastated St Mark’s church in Maida Vale] very much in my mind just now.”
LFB Station Commander Steve Howlett, who was at the scene, said: “Firefighters worked incredibly hard to ensure everyone was accounted for and there were no remaining hot spots.
“The Brigade’s drone team were able to use drones to survey the incident from above and relay images of hard-to-reach areas to incident commanders.”
The cause of the fire is not known at this time.
