A pregnant woman was among 25 people rescued from a fire which continues to rage through a shop and the flats above in Finchley Road.
Seventy firefighters were called to rescue residents of the flats above the PhoneRepairs4u shop at 6.24am.
The pregnant woman and her husband were rescued from the roof by crews using a turntable ladder.
Paramedics treated 12 people for smoke inhalation at the scene and a two-year-old child was taken to the Royal Free Hospital in Hampstead as a precaution to treat smoke inhalation.
Station manager David George, who was at the scene, said: “Firefighters are working hard in strenuous conditions to contain this fire and bring it under control.
“On arrival crews wearing breathing apparatus entered the building and led over 20 people to safety from inside.
“We also used one of our turntable ladders, which is like a cherry picker, to rescue a further two people from the roof.”
Firefighters are expected to stay at the scene for most of the evening as the fire has swept into the voids between the floors of the building.
Officers wearing breathing apparatus have now entered the building to tackle some “deep-seated pockets” of fire.
According to a spokesman, the fire has now been contained but smoke is still billowing from the roof and the front of the shop, near the O2 Centre.
The Ham&High was on the scene to film a firefighter breaking a first floor window above the phone shop, causing plumes of smoke to gush out.
Retired Daniel Levin, 71, was on his way to use an Internet cafe on the same strip of shops when he saw the fire.
Mr Levin, of Aberdare Gardens, South Hampstead, said: “I could see there were blue and white lights, so I thought there was an accident.
“It wasn’t until I got to Finchley Road Underground Station and then I could tell there was a fire and I could see the smoke.”
At 2.42pm, Finchley Road Underground Station closed due to a “local power failure” as a result of the fire, a spokeswoman confirmed.
It has sine re-opened for the Jubilee Line only. The Metropolitan Line remains closed at the station.
Police have put road closures in place around the station between Compayne Gardens in South Hampstead and Arkwright Road in Hampstead. Finchley Road is likely to be closed for at least the next few hours.
There are severe traffic delays tailing back past the O2 centre and past Swiss Cottage.
Traffic is being diverted, and coaches including National Express services have been delayed.
Most of the O2 Centre is still open, except for Habitat and Tiger.
The cause of the fire is currently under investigation.
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