At the front of the room, we see Steven Frank, a Shoah survivor now in his 80s, sitting in a comfy-looking red leather chair.

“What was the first thing that made you smile after the Holocaust?” someone asks.

“My goodness me, that’s a difficult question to answer,” he replies.

“I suppose the first thing that made me smile was when I had a cup of tea with condensed milk. That to me was nectar from the gods — real tea — warm and with the sweetened condensed milk. It’s something I will never, ever forget.”

There are other questions: Why Mr Frank believes he survived; the last thing his father said to him. After a short pause, each is answered. A group of visiting schoolchildren pose additional questions. Again, each is responded to.

Talking to a Holocaust survivor is always profoundly moving. The difference this time is that the survivor has not been in the room with us. We have been conversing with Steven Frank’s 3D projected image.

It is a first experience of the Forever Project, the centre’s answer to a question which is becoming more pressing as the years go by. What will be the impact on Holocaust education and awareness when there are no survivors left to recount their experiences to new generations?

“The average age of survivors now is in the mid-80s, maybe a bit higher — and we lose some every year,” says Phil Lyons, the centre’s chief executive.

“We’ve got every one of the people who have spoken here on film. But how do you recreate that ability to be surrounded by the story and be able to ask questions?”

Over the past two years, 10 survivors have been interviewed for the project. Filmed in York in front of cameras shooting in stereoscopic high definition, each was asked around 1,000 questions on every imaginable aspect of their wartime experiences.

Although it was an emotional process, Mr Lyons says “the only time some of them really wept is when I met with them to ask them if they’d do it.

“I explained that we would have their testimony as a legacy for this centre going forward and that people in 100 years’ time would be able to watch it.

“They were very affected by the idea that ‘my story will be heard, we will keep the memory alive’. And so was I.” No survivor had declined the invitation to participate.

A few days after seeing Mr Frank in 3D, I met him in real life at the Holocaust Memorial Day ceremony at London’s City Hall. He said he was “honoured” to be the first subject.

“I was filmed for a week. It was quite exhausting but incredibly satisfying. I think it’s absolutely fantastic because although most of my grandchildren have heard me speak, my great-grandchildren aren’t here yet. It’s incredible that they and the generations after them will be able to hear me.

“I have seen myself, even asked myself a question and seen myself answer it. It’s a very strange thing.”

The project is still in its testing phase, with only Mr Frank’s testimony currently available.

“We’re going to be launching the interactive testimony of each of the individuals during the course of this year,” explains Sarah Coward, the project leader and the centre’s deputy CEO. “One of the reasons we wanted to do that is to give each person their moment rather than releasing them all at once.”

The project uses a high level of technology. “There are an enormous amount of steps the system is dealing with,” Mrs Coward says. “But the speed of the response, given what it’s doing — taking what you’re saying, converting it into text, applying that to the system and replaying the right answer — is remarkably fast.”

Adds Chris Walker, managing director of Bright White, the technical team behind the project: “There are a variety of different software modules in there. But I feel the one people mostly want to know about is the natural language processing software.

“It’s tolerant to the way in which people speak, dealing with accents very well and age differences effortlessly. It also deals with different phrases you might use to approach a given question, as well as determining and standardising terminology.

“A good example would be one of the camps, known in this country as Theresienstadt but which is pronounced slightly differently in other languages — Terezin. Those names are interchangeable for the computer, as are different words like ‘father’, ‘dad’ and ‘daddy’.”

The project has cost around £1.2 million, which will rise if other survivors are filmed.

“We were lucky enough to have support from the Heritage Lottery Foundation Fund, the Department for Communities and Local Government and the Pears Foundation, as well as a range of other trusts, foundations and individuals,” Mrs Coward says. “The support of the Association of Jewish Refugees was also really important.”

Another key aspect of the project has been evidence. “You know what the world contains in terms of denial, in terms of sceptics and cynics,” Mr Lyons says.

“As we move away from first-hand testimony, we have to have absolute provenance, we have to have evidence, we have to have a documented timeline.

“We have a curatorial team who are doing a huge amount of work on making sure that what is said can be evidenced.”

Each answer from a survivor has also been logged and filed to prevent anyone in the future claiming that it had been given in response to a different question.

“If anybody ever does question the legitimacy of the answer given, we can always track it back to the studio, where you can hear the question being asked. It’s all traceable primary source historical evidence. We don’t edit any of the testimony at all.

“Also, we made it clear in the process that we wanted the answers the survivor gave to be natural, so we didn’t pre-warn them of the question.

“It was tempting sometimes, because with some questions we know they could have answered better. But we didn’t say: ‘You should say this’. That would be wrong ethically.”

Present in person at the centre was Mala Tribich, another of the survivors filmed for the interactive project.

“To tell you the truth, when I first heard about it I thought: ‘That sounds a little bit weird – bringing me back to life’,” she admits.

“But I thought about it very carefully and came to the conclusion that this will be more powerful than reading a book, perhaps. It can help someone to know more about it and try and do something to try and avoid it in the future.

“And I think they draw some sort of inspiration — and they tell me they do — from hearing about it from someone who was there.

“The alternative is watching an ordinary film. But that has no question and answer. I think this will have an impact. People will want to watch it, if at first only through curiosity.

“I’m hoping all the work that we do — myself and a lot of other Holocaust survivors — will prove to have helped. We will never know. We won’t be around to see.” And some participants have requested that certain answers they have given should not be made available until after their death.

“The technology can never really replace people, no matter what you do,” Mrs Tribich concludes.

“But it makes it a bit easier to take in [the Holocaust memories].

“It is the closest people are going to be able to get because there will be nothing else.”