Celebrity brings privilege and for Robert Rinder the “apex of that privilege” was the opportunity to appear in the BBC’s Who Do You Think You Are last year.

Best known for his ITV reality court room show Judge Rinder, the presenter followed the story of his grandfather, hearing first-hand testimony in Poland of the horror of Nazi forced labour camps, as well as the hope offered by a new life in Lake Windermere.

Watched by 8 million viewers, Mr Rinder’s episode of the hit genealogical series went on to win a BAFTA earlier this year.

Last weekend the 41-year-old Londoner, who is a barrister, told an audience at the Migration Museum that he had only “crumbs of detail” about his maternal grandfather’s past prior to participating in the programme.

“He never spoke about it,” Mr Rinder said of Morris Malenicky, who was born in Piotrkow in Poland and was the only member of his family to survive the Holocaust.

Addressing a captivated audience at the museum’s Family History Day of talks and workshops, he said: “There was never a moment where he sat down and went through a coherent narrative.”

Currently based in temporary premises, the museum tells the long story of movement of people, both to and from Britain, through the ages — and the many ways it has shaped British society.

Surrounded by pictures and stories of new arrivals from the Caribbean, Mr Rinder spoke with great appreciation of the BBC opportunity. Aware that many in the room had no doubt spent years, if not decades, researching their own past, he paid tribute to the hard work of the programme’s research team.

His role, he said, was minimal. “I showed up, I was moved, I read the documents, I cried.”

Yet those there to hear him speak had no doubt of the impact the process had had on him and, subsequently, on viewers and the wider community. You could hear a pin drop.

He recalled his childhood relationship with his grandfather, who would regularly take him and his brother to Speaker’s Corner in London’s Hyde Park, even though that often meant listening to “antisemitic bile”.

Mr Rinder: “I remember him holding my hand and saying, ‘You see, in this country this man can say whatever he wants’.

“It was only later I came to understand what that meant to him — what being British meant to him. This was someone who had quite literally touched the face of tyranny.”

The audience heard about an earlier visit to Poland that he made with his grandfather in 1997 while still a student.

“I wasn’t ready for what I saw,” he said, recalling how his grandfather had taken him back to a glass factory where he had been a slave labourer, as well as the apartment block where he once lived.

During the visit an old woman emerged from the building and exchanged a silent look with Morris, which his grandson failed to appreciate at the time.

The pair had recognised each other, their silent look speaking volumes about the secrets of their shared past.

Morris died in 2001 aged 78 and with him went the story of his past. But years later when his grandson returned to Poland with a camera crew, some of those secrets were unravelled.

There he was joined by a man called Natanel who had a deeply personal story to share with the presenter. Their grandfathers had been best friends and his had written a detailed “almanac” of their shared times together.

These tales brought to life his grandfather’s close family, all of whom perished in the Holocaust.

“It gave them neshama, or soul, as my grandfather would have said,” said Mr Rinder.

At the end of the war Morris was liberated from Theresienstadt and became one of several hundred orphaned refugee children who was brought to Britain, where he started his new life in Windermere, in the Lake District.

Mr Rinder described how in later years Morris went on to become best friends with “Murphy”, a fellow immigrant from St Lucia. “They loved this country and they had this sort of commonality,” he said, explaining that both were hugely proud of Britain’s democracy and enduring rule of law.

The experience of making Who Do You Think You Are endowed him with a sense of “optimism”, though he acknowledged that that is becoming “increasingly challenged” by the rise of right-wing populism across Europe.

He told the audience about a new two-part documentary for the BBC in which he takes descendants of other Holocaust survivors on journeys similar to his own.

He hopes the programme, entitled My Family, The Holocaust and Me, will shine a light on the trauma inherited by second generation survivors and indeed society overall.

“The point of the documentary is to remind ourselves of the fragility of all this and to safeguard against complacency,” he said.

This sentiment is shared by the team behind the museum whose overall mission is to “show how migration is a subject that is relevant to all of us,” according to Matthew Plowright, head of communications. Migration has long been a political issue but the museum aims to highlight the “personal realm”.

Backers came together to “fill a gap in the cultural landscape,” according to Mr Plowright, who added: “It can be a forum to help bring people together and explore and discuss, away from the often quite angry and discriminatory political sphere and social media.

“If you humanise and make connections you can reach a different starting point — who are we individually and collectively? Where have we come from and where are we going?”

A host of organisations were on hand at the event to help visitors do just that — uncover their past in order to better make sense of their present and future. Among them was the Jewish Genealogical Society of Great Britain, JGSGB. Their stand was replete with literature and information and manned by a host of enthusiastic volunteers, one of whom proudly donned a badge stating “I seek dead people”.

With eight great-grandparents born in Eastern Europe, Leigh Dworkin, chairman of JGSGB, has had no shortage of migration stories to research.

“Jewish people are quite famous for their migrations,” he said. “But it isn’t just the Jews. After us came the Bangladeshis and before were the Huguenots.

Genealogy is a hugely popular hobby and the internet attracts more followers every day, according to Mr Dworkin.

“Genealogy is really all about story-telling,” he said. “It isn’t just names and dates.

“What we really want to know is what’s the story of the people whose lives we are looking in to and what’s the story of our search for them.”

Technology and the internet have been nothing short of revolutionary for genealogists, while programmes like Who Do You Think You Are and ITV’s Long Lost Family have fuelled the public’s fascination.

“The only trouble with the TV programmes is that it all takes place in an hour,” said Mr Dworkin.

“The reality is that to solve all the different genealogical problems does take time. You go to the archives and there isn’t going to be a film crew there to see you cry.

“It doesn’t mean it has to be hard but it does take some effort. There’s a lot of information online and more and more records are becoming available.

“It’s very rewarding, though occasionally you do come up against brick walls which you may nibble away at for several years.

“But when they fall, it’s amazing!”

If you would like to find out more about the museum visit their website here, or to learn about the JGSGB go here.