A London council expressed its "sincere regret" as it pleaded guilty to four charges relating to a tower block fire which killed six people.
Three women and three young children were killed in the 2009 blaze at Lakanal House in Camberwell, Southwark Crown Court heard.
The fire started due an electrical fault with a television.
Southwark Council pleaded guilty to charges relating to safety breaches and must pay £300,000 costs.
The council will be sentenced on Tuesday, where it is expected to be fined.
Dayana Francisquini, 26, and her children, six-year-old Thais, and Felipe, three, were among the victims.
Helen Udoaka, 34, her three-week-old daughter Michelle and 31-year-old Catherine Hickman were also killed.
They all lived on the 11th floor.
The charges, dating from 1 October 2006 to 3 July 2009, include a failure to carry out a suitable and sufficient risk assessment, failure to take general fire precautions - including in relation to safety of employees - and a failure to ensure that premises were subject to a suitable system of maintenance.
The council was taken to court by London Fire Brigade.
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 court heard deficiencies included:
- 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
- Inadequate fire-resisting boxing-in (or fire protection) to the timber stairs where they cut across the common corridor
Richard Matthews QC, for the council, expressed "sincere regret for the failures that were present in the building".
The court heard there had been a major refurbishment on the building in 2006 and 2007.
Mr Matthews said it was a matter of "enormous disappointment and regret" that those works did not identify failures in boxing-in, failures in the ceilings and failures regarding signage on balconies.