Transport for London and the operator of the Croydon tram have been fined a total of £14m for safety failings leading up to the 2016 crash in which seven people died.
Both TfL, which was responsible for the track network, and Tram Operations Limited, a subsidiary of FirstGroup, pleaded guilty to health and safety offences.
TfL was fined £10m and TOL fined £4m at the Old Bailey on Thursday after a three-day hearing.
Neither body had conducted a risk assessment for the possibility of a derailment before the crash, which occurred when a speeding tram overturned at a sharp turn approaching the Sandilands junction in Croydon on 9 November 2016.
Seven people died and 61 were injured, 19 seriously, in the crash. Accident investigators found that another tram had nearly overturned shortly before the fatal incident.
Mr Justice Fraser told the court: “This was undoubtedly an accident waiting to happen, quite literally.”
He said there had been a failure to heed warnings about the risk of drivers becoming disoriented in the Sandilands tunnel network on the approach to the bend, and the report of a “near miss” just days before the crash had been ignored.
The judge said the “complacency” around inadequate lighting and visual cues in the tunnel before the bend was disturbing.
A number of additional measures have since been put in place including new systems to prevent trams over-speeding and to manage driver attentiveness, and the placement of more warning signs at Sandilands and other risk areas along the tram routes.
TfL and TOL were also ordered to pay costs of more than £230,000 each to the prosecuting authority, the industry regulator the Office of Rail and Road.
The tram driver, Alfred Dorris, 49, was last month found not guilty of failing to take reasonable care of his passengers.
The ORR’s chief inspector of railways, Ian Prosser, said: “When faced with the evidence of their failure over a number of years, both TfL and TOL accepted that they had not done everything that was reasonably practicable to ensure the safety of their passengers, with terrible consequences on the early morning of 9 November 2016.
“We must never forget the tragedy of that day, and must strive to learn all of its lessons so there can be no repetition. Our thoughts remain with those whose lives were so affected.”
Andy Lord, London’s transport commissioner, said: “I apologise on behalf of everyone at Transport for London, both past and present, for this tragedy and for the pain, distress and suffering that all those affected have endured and continue to endure.
“We accepted responsibility promptly and we did everything possible to ensure the right support was quickly in place to help all those affected.”
He said the tram network had undergone a programme of major safety improvements since 2016.
“We continually review our network and work with the wider tram industry to ensure we are running the safest possible service for our customers and to ensure that such a tragedy can never happen again.”
The seven passengers who died were Dane Chinnery, 19, Philip Seary, 57, Dorota Rynkiewicz, 35, Robert Huxley, 63, and Philip Logan, 52, all from New Addington; and Donald Collett, 62, and Mark Smith, 35, both from Croydon.