The wife of the billionaire businessman and his son who died on the doomed Titan submersible has told of her determination to ensure that future deep sea diving vessels are regulated – so no one has to suffer as she has.

“I just don’t ever want this to happen again to anybody,” Christine Dawood says. “I would never want anyone to go through that pain.

“I want there to be strict regulations that forbid companies or individuals to do such a thing without having to prove certain parameters. A car manufacturer will not be allowed to license a car out to the public without going through X, Y, Z tests, and I want that to happen for this sector as well, so that you can’t release a vessel that is not fit for human travel.”

In June 2023, British-Pakistani businessman Shahzada, 48, and university student Suleman, 19, were among five passengers who perished when the Titan imploded 90 minutes into its voyage to see the Titanic. The others were Titan’s owner, OceanGate CEO Stockton Rush, 61, British businessman Hamish Harding, 58, and former French navy diver Paul-Henri Nargeolet, 77.

Following its investigation, the US Coast Guard will make its official report into the disaster, which happened when the carbon fibre vessel had nearly reached 4000m below sea level, later this year. But a new BBC documentary had unprecedented access to the USCG investigation and the film contains damning testimonies which point towards criminal negligence.

But Stockton is shown laughing off safety advice and warnings from staff and other experts despite repeated problems with the Titan submersible. Noises recorded during test dives, described at different times as “cracking” or “popping” indicated that the hull was breaking up – a process known as delamination.

Speaking to The Mirror, German-born Christine, from Surrey, said her family fell for the hype when it came to booking the trip – which cost an eye-watering $250k each – because Shahzada and Suleman were fascinated by The Titanic, and Stockton was brimming with confidence about taking them to see it.

“I guess the American way of talking and presenting themselves is very different to ours, so I just thought they are a lot more egocentric. I mean, there is a lot of, ‘We are awesome,’ and the American dream, and, ‘We can do it.’

“I wanted to hear the confidence of the person who built it, who ran the company, but also he surrounded himself with literal experts. I mean, one died with them. If you have an expert like this with you, I mean, you don’t doubt.”

She said that Shahzada and Suleman were not daredevil thrill-seekers but simply filled with curiosity. “We just thought it would be a really lovely experience, a little bit out of one’s comfort zone, but still,” she explained. “My husband always loved the story of the Titanic and they did this exhibition all over the world for the 100-year anniversary. We saw it in Singapore as a family, and afterwards Suleman made a papier-mâché Titanic because he was just fascinated.”

But having heard what was said at the public hearings in South Carolina last September, she now struggles to comprehend how OceanGate was able to operate unchallenged. “The arrogance of the people in charge when they think that they’re above everything. That really gets to me. Why is ego and arrogance more important than safety? The irony is not lost on me that the Titanic sunk for exactly the same reasons,” she says in the film. “We all know who the culprit is – it’s not changing anything. The culprit died with them so, who am I to blame?”

She was too grief-stricken to attend the public hearings in person but listened from her home in the UK and said what she heard felt “like a real crime horror film”.

Christine, 49, has agonised over wishing she had stopped them from taking the voyage, but was relieved when the Coast Guard assured her afterwards that it could not have been predicted by those on board or their families. “I don’t think you can ever get closure, but it helped with moving forward that they kept on saying I could have not known it,” she says. “There was an element of doubt in myself, did I miss something. What could I have done differently? This is the life of my son and my husband they are talking about – so it is deeply personal.”

Despite this, two years on she has worked hard to ensure that feelings of anger and bitterness do not take over. “There’s a feeling underneath, which is the grief, which is the loss, which is the loneliness. Christine says that whatever the USCG investigation concludes in terms of blame and responsibility no longer matters to her – so long as the rules governing the trips are changed to prevent future disasters.

“For me personally, it actually doesn’t really make a difference because first of all, what’s the point of blaming? It’s not good for my mental health and it’s not going to bring them back. There’s a feeling underneath the anger, which is the grief, which is the loss, which is the loneliness. I just decided that I need to concentrate on those true feelings. Knowing that it’s negligence, does it give me a relief that it wasn’t my fault? I don’t know.”

Christine, who also has a daughter, says that confirming how quickly the implosion happened did bring some shreds of comfort. “When we heard that it was instantaneous, we were like, ‘thank God they didn’t suffer’,” she says quietly. “They didn’t suffer in the moment and they didn’t know it was coming because it was so fast, so they would not have had any fear. But the bigger relief almost was that for those four days, they weren’t stuck down there where you can’t get out, so deep under water.”

Christine is now honouring her son by walking 800km from Surrey to Glasgow, where Suleman was at university, because he’d told her it was something he’d wanted to do with her. She started the five-week walk on Monday and hopes to finish on June 23. Calling the walk The Pathway of Light, she said: “Walking was our thing, he loved walking and so did his dad. Whenever we wanted to talk about something, just to have some mother-son time, Suleman would join me on the early morning walk with the dog. Now I am joined by friends and family and we walk, and we talk and we remember them.”

Planning the challenge has also helped Christine to deal with the grief and anxiety she has been left with following the tragedy. “Walking in the fresh air has really helped. I always ask, is it helpful for me if I’m now going to get angry? Is it healthy? Does it bring them back?” she says. “And if the answer is no, then I try to stay away from that feeling.”