Britain’s deadliest fire in more than a century raced from floor to floor, forcing residents to decide: Wait for rescuers or disobey orders and try to escape?

Aalya Moses was having trouble sleeping just before 1 a.m., when she heard frantic knocking. Her neighbor, Behailu Kebede, said his refrigerator had caught fire.

“He looked so scared, so frightened,” Ms. Moses said. “I phoned my daughter and she said to me, ‘Just get out of the house.’”

She passed firemen going up the stairs. Outside, she saw that the blaze had spread from her neighbor’s unit and raced up the side of the building.

Miguel Alves was in the elevator when it stopped on the fourth floor and opened to a thick cloud of smoke.

He ran upstairs to his 13th-floor apartment to get his children. The authorities told his wife, who was already outside, that they should stay there.

But the message didn’t reach them in time, and they escaped down the stairs, he told The Guardian.

Toxic smoke began to make escape difficult. Mohammed and Omar Alhajali, Syrian refugees and brothers, tried to escape together from the 14th floor.

But they became separated in the stairwell. “It was too dark in the corridor, and the smoke was too thick,” Omar said.

He continued and was rescued by firefighters. Mohammed turned back and was trapped.

Others decided to stay. A neighbor told Meriam Antur that she had to wait in her 19th-floor apartment with her two young children.

Ms. Antur waited as smoke filled up the hallway. “I got into my flat and put a towel in the door and started to pray,” she said.

Firefighters eventually arrived and led them down — three of the 65 people they rescued that morning.

At 1:38 a.m., Rania Ibrahim broadcast a disturbing live video from the top floor, where she and others were trapped.

She called out from her balcony: “We’re stuck on the 23rd floor! Hello!”

Ms. Ibrahim opened the door to a hallway thick with smoke, and at least one person rushed in.

Ms. Ibrahim is among dozens who are missing and presumed dead.

Outside, crowds watched as the building burned.

Less than an hour after the fire started, most of the floors on the northeast corner of the building were engulfed.

People stood at their windows as flames approached their apartments.

“Please pray for me and my mum,” Khadija Saye messaged her friend from the 20th floor. She was one of the first victims identified by police.

Just after 4 a.m., a woman could be heard screaming from the 11th floor. People on the ground shouted to fill her bathtub with water until firefighters arrived.

As late as 5 a.m., a man on the eighth floor was seen waving a white flag. It is unclear whether he managed to escape.

As dawn rose, the fire still burned. It was not brought under control until more than 24 hours after it began.