On March 6, 1987, a car ferry bound for Dover capsized near the Belgium port of Zeebrugge, killing 193 people.
The tragedy happened just before 7pm and it was just 90 seconds into the voyage that the ship started to overturn.
The Herald of Free Enterprise had left Zeebrugge carrying extra water in her ballast tanks and with the bow doors to the car deck still open. There was no time to send an SOS.
Many of the 650 passengers on board were Brits who had taken advantage of a deal in The Sun newspaper offering cut-price ferry crossings.
Among them was Lisa Ladybird, of Burton Latimer. She was just four at the time but has vivid memories of what happened.
She and her parents were never meant to be on board the boat, but they had missed their earlier ferry crossing.
Lisa’s family had used the newspaper deal to visit some relatives in Belgium and were joined on the trip by her mum’s best friend Caroline and her husband Nick.
Lisa, now 29, said: “With it being quite late I remember being asleep for most of the journey up to the port and when I woke up we were in the departure lounge. Apparently we had missed our ferry and we had to go on the next one, which was the Townsend Thoresen ferry.
“On board we went into the lounge and my parents wanted to go off to the duty free to get some last minute bargains so I sat with Caroline and Nick.
“I told Caroline I needed to go to the toilet. A fire suddenly broke out in the sanitary bin and Caroline had to grab a fire extinguisher to put it out.
“As we left the toilets, the ship jolted. The floor was really slippery and I fell. I remember Caroline saying it must have been a bit of rough water but the ship jolted again.”
Lisa describes the floor as being at a 45-degree angle and she recalls Caroline telling her they were going to have to jump.
“The only exit was double fire escape doors which led to a drop into the icy water below. To me it looked like a big jump and underneath us was water. That’s when I got scared.
“Caroline jumped and I hung on to her with my arms around her neck. I remember hitting the water and it was so cold.
“The cold must have knocked me out because then I remember waking up and the whole place looked like a cave.
“There was a girl in the water near us who was a bit older than me and Caroline was talking to her and trying to reassure her.
“When I next woke up again they were both screaming, really loud screaming. There was an opening ahead and they were waving at a helicopter overhead.”
Lisa doesn’t remember much about being rescued from the boat. Her next memory is of being in an ambulance.
“I had been wrapped up in a blanket like a baby and I could hear a woman crying, saying she had lost her baby and could anyone find her. I felt my blanket being pulled away from my face and she said, ‘It’s not my baby’.”
Lisa was taken to one of the local hospitals and she remembers asking one of the nurses where her mum was. It took them some time to find out which hospital she was at and later that night Lisa was taken to be reunited with her.
Her mother had a massive gash to her wrist and one to her leg. “Out of the five of us, she was the worst injured,” says Lisa.
“I remember my father walking on to the ward. I was so pleased to see him and he picked me up.
“He had been in another hospital and he had no injuries whatsoever.”
The family spent a few days in Belgium while Lisa’s mum recovered from her cuts. Members of the Royal family and the Prime Minister at the time Margaret Thatcher went over to Belgium to visit the British survivors in hospital.
Lisa said: “I shook Prince Charles’s hand. He was really lovely and he spoke to both my parents and to me. He asked me how I was.”
When they were ready to return home, the family had to travel by ferry because Lisa’s mum is afraid of flying and Lisa remembers her being very unsettled during the voyage home.
The disaster made news around the world and there was a huge amount of media interest around the survivors.
Lisa’s family appeared in several national newspapers but her parents did not enjoy the attention and were keen to start getting their lives back to normal.
Over the years the family lost touch with the friends who joined them on the trip but last summer Lisa managed to trace Caroline, the person she says saved her life that day.
Lisa said: “You can never forget what happened. Every year at around this time I start to get nightmares and I need to talk about it to someone.
“When you have been through that trauma and seen what you’ve seen, some people don’t want to go down that road again but this is my therapy.”