From You Tube; Six people including a three-week-old baby have died in a huge fire at a tower block in London.

"There were six fatalities - three adults and three children," a London Fire Brigade spokesman said after the overnight blaze in Camberwell, south London.

Some 30 people who were trapped inside have been rescued. The blaze is under control.

Witnesses gave distressing accounts of how those trapped by the fire screamed and pressed their faces up against the windows as they battled to escape the flames and smoke.

The Metropolitan Police said that those who died were a three-week-old baby, two children aged about six and seven, a woman in her 30s and two other adults.

A further 12 people were taken to hospital, many suffering the effects of smoke inhalation.

About 100 firefighters were sent to the fire, which started on the fourth floor of the local authority-owned block and spread to the 11th.

The fire took hold just before 4.30pm, 1.30am (AEST).