How I'm a Celeb castle saved hundreds of children during World War II

While millions of viewers watched contestants battle bushtucker trials and the Welsh winter on I'm a Celebrity... Get me out of Here, none of them would have glimpsed inside Gwyrch Castle's derelict dining room.

The walls stripped bare and a mix of mismatched furniture, it is hard to believe that it served as a safe haven for hundreds of young refugees during the Second World War.

Sonia Eberman, 102, who now lives in Australia, was one of the children rescued as part of Operation Kindertransport and remembers having to clean the castle "before we could live in there".

The Grade I listed castle's little-known secrets are uncovered in a new Sky History programme, which follows one of the country's most at-risk historical buildings' restoration work.

The Kindertransport scheme rescued more than 10,000 mainly Jewish children from Nazi-occupied countries, and brought them to safety in the UK.

Housed in foster homes, hostels and farms, every child needed a sponsor to offer accommodation before they were granted asylum.

That is where the 13th Earl of Dundonald, the son of the castle's owner, stepped in and offered his family home as a refuge.

Gwyrch Castle custodian Mark Baker said: "When they arrived the castle was virtually empty.

"The family had put all of their private contents like portraits and furniture into several locked rooms so they had the run of you know the whole of the place basically.

With the castle not lived in properly for the previous 15 years, some of the reports from the new residents included exploding toilet drains and insufficient heating.

Most of the children were unaware about why they were at the castle, as life carried on as normal with lessons, work and even a wedding.

"Lots of them got work in the wider castle estate, so things like on the farms," Barker said.

"Some of them worked in the forestry side with the woods people, cutting down trees, processing wood.

"I think one of them helped with the local milk deliveries and they really kind of became quite integrated into the local area."

More than 10,500 miles (16,898km) away, Benjamin Preiss from Melbourne, Australia, first found out about his grandmother's links with north Wales through old letters.

Speaking on Sky History's Great British Castle Rescue, Preiss said: "It started as a little bit of a journey to learn more and find out more."

That journey led Preiss and his mother Sandra to travel from the other side of the world to visit a part of their family's history.

"I wanted to walk on the same steps that my grandmother did," he said.

His mother added: "Gwyrch Castle is part of her survival story, and therefore mine, and therefore [Benjamin's].

"Trying to understand how it would've been for a 16-year-old girl to land in a foreign country on her own, having left her mother and older sister behind."

Eberman remembers "working in the fields [and] working in the farms" during her time at the castle.

She said: "And of course, in the beginning [working on] the steps.

"We had to clean the place up before we could live in there."

Speaking to her family on the phone from Australia during their visit, she said: "It's amazing that you've been to the place I've been to."

Despite hoping for a peaceful life among the forests of Conwy, north Wales, the lives of the children were in danger when the 18th Century castle became an unlikely target during the Blitz.

As German planes targeted nearby Liverpool, Gwyrch Castle, which was on the Luftwaffe's route home, was also bombed as pilots hoped to lighten their load for the journey back to Europe.

"Because the castle is such a big structure, it's white limestone so on a moonlit night it's quite visible," said Baker.

"So you can imagine being here, everything's pitch black then, suddenly, 'bang'."

Because of the attacks, the castle's 200 residents had all been moved elsewhere by the end of 1941.

But 50 years later, the castle fell into disrepair at the hands of an American absentee owner and is now considered one of the country's most at-risk historical buildings.

Baker passed the castle almost everyday on his way to school and is passionate about restoring the estate.

Speaking on the programme, he said: "The castle, it was like an apocalypse.

"So beautiful and really cherished by local people and I saw it disappearing into the hillside.

"That really pushed me into wanting to do something, to try and save the place."

The gothic castle has been given £200,000 in funding by the National Lottery to help kickstart work on the building of "national importance".

The start of Gwyrch Castle's restoration features on Great British Castle Rescue on Sky History.