Southwark Council has been ordered to pay £570,000 after three women and three children were killed in a tower block blaze.
The inferno, caused by an electrical fault in a TV, ripped through Lakanal House in Camberwell in 2009, leaving six people dead.
Southwark Council was taken to court by the London Fire Brigade on four charges in relation to safety breaches.
At Southwark Crown Court on Tuesday the authority was fined £270,000 and ordered to pay £300,000 towards the fire brigade’s court costs for bringing the prosecution.
The council had pleaded guilty to the charges at the same court.
Designer Catherine Hickman, 31, who had been commissioned for work by the singer Bjork, died in the blaze alongside Helen Udoaka, 34, and her three-week-old daughter Michelle.
Dayana Francisquini, 26, and her children, six-year-old Thais and Felipe, three, were also killed.
Stephen Walsh QC, for the London Fire Brigade, said: "It is of great importance that I make the point that this prosecution is concerned with the risks prior to the fire.
"It is not alleged that the breaches were causative to the fatalities in the fire itself."
The charges, dating from October 1 2006 to July 3 2009, include a failure to carry out a suitable and sufficient risk assessment, failure to take general fire precautions and a failure to ensure that premises are subject to a suitable system of maintenance.
Deficiencies identified included the absence of strips or seals on doors in the building, suspended ceilings which lacked cavity barriers which could have reduced the risk of fire spreading, and inadequate fire protection for the timber stairs.
Richard Matthews QC, for the council, expressed "sincere regret for the failures that were present in the building".
