When Renee Salt closes her eyes, she can still visualise her elegant, well-dressed mother, Sala. “Lovely skin, beautiful hair. She was my whole life, such a loving kind mother,” she tells me of her devoted parent who died 12 days after the liberation of the Bergen-Belsen concentration camp aged 42. “It was an idyllic childhood full of love. She would sit and read with me and my
little sister or take us for walks in the park to play with other children. She wanted us to go to Paris for further education.” It seemed unimaginable that just a few years later, after Germany invaded Poland, Sala would be forced to try to save her
two daughters by hiding them under her coat as the Nazis liquidated the ghetto where Renee’s family had been sent. When Renee’s little sister was marched off to certain death, Sala fought to ensure her elder daughter remained safe through the horrors of Auschwitz and Bergen-Belsen – giving mother and daughter something beautiful to cling to in a depraved world. “We lived for each other, and it was all God’s wonder and will,” Renee, now 95, and also known as Renia, says. “Once in the ghetto, mama exchanged her cardigan for a cabbage, to give me a taste of some other world. “By the time we got to Auschwitz three years later, we were so hungry we’d have eaten a piece of wood.” It was August 24, 1942 – just 16 days after Renee’s 13th birthday – when her family was cruelly torn apart. By this time, they had lost their home in Zdunska Wola, in central Poland, to the Nazis and, like many other Jews, were living in a ghetto. Then came the fateful day an order crackled over a loudspeaker directing the terrified occupants to gather and sit down in the square. Then came the second order: “Parents should hand over all children up to 18 years of age.” Renee’s eyes spill with tears as she speaks in Polish-accented English, eight decades later: “It’s not possible to describe this scene. I can only give you an idea about it.” She saw children large and small, including toddlers and babies, forcibly separated from distraught parents. “Some of the big ones were carrying younger siblings. They were put in covered lorries and taken away,” she says in faltering sentences. The crying of the children, and the screaming of their mothers, still rings in her ears today. “My mother tried to hide Stenia, who was 11, and me, who was two years older, by covering us with her coat.” But a guard noticed what she was doing. “She tried to hide me on one side and my sister on the other, but the Germans got hold of Stenia and my mother got a beating. A guard was hitting her everywhere. “My sister begged him, ‘Please don’t hit her. That’s not my mother’. A small girl with tears running down her face, trying to protect our mother. It is one of the most horrible things.

“We were two peas in a pod. We played together, we were always together. Then, after our mother was beaten, Stenia was taken away from us with tears running down her face. We never saw her again, but I know what happened to her. It felt like my heart had been cut in half.” Sala tried to cope with the unfathomable loss by pushing all her survival instinct into Renee.

“She was broken-hearted, in a terrible condition. I tried to protect her, but she was never the same.”

Moments later, lorries left the square with their cargo of sons and daughters. “Stenia, along with several hundred other children, and the elderly and sick from the ghetto, were driven 75km to the Kulmhof death camp in Chelmno, 200 miles west of Warsaw,” says author Kate Reardon. She has helped Renee to write her haunting life story, A Mother’s Promise, through the prism of Sala’s extraordinary acts of devotion.

“She kept me safe from 1939 to 45,” says Renee. “It was all God’s wonder and will.”

That she survived to tell her tale is a tribute to her mother’s selflessness and heroism.

From invasion to liberation in April 1945, Renee was marched, herded and shoved from ghetto to camp.

But there was one constant: her mother.

“Every day for nearly six years, mother and daughter were tangled together in hell,” says Kate, who supports Renee throughout our interview. “From ghettos to slave labour, they were a powerful source of solace and hope to one another.

“For Renee, the need to share has finally overcome the desire to forget. This is a love letter to a mother 80 years in the making.”

Against the backdrop of unimaginable cruelty came acts of life-enhancing kindness. To protect her, some of the other survivors helped 13-year-old Renee look older.

“One had a lipstick in her pocket, and another a powder compact. One lady exchanged her high-heeled shoes with my flat ones,” Renee recalls.

She was 15 when she boarded a train to Auschwitz with her parents.

She writes of trying to “concentrate on the feeling of holding my mother’s hand in mine. It was like holding on to life”.

On arrival, her beloved father Tatus jumped from the train and was marched out of sight by the SS.

For 80 years, Renee believed her father died in the gas chambers. She never had a chance to say goodbye. Bewildered, Renee and her mother shuffled forward in the queue for selection, and towards the notorious Dr Josef Mengele, who was called the “angel of death” for his inhumane medical experiments on Auschwitz prisoners.

Renee was sent to the right, to work, and her mother to the left – to die immediately. But Sala crossed the selection line back to Renee’s side.

To this day, Renee cannot fathom how her mother’s move went unchecked. “It was like a miracle,” she says. “They must have seen it, there was no way they couldn’t.”

For the next month, the pair survived starvation, beatings and the unbearable cold before being transported to work in Hamburg. There, through the coldest winter of war, they worked cleared rubble from bombsites in the Hamburg docks.

“I didn’t even have underwear and my head was bald from where it had been shaved,” recalls Renee. “Nearly every day there were Allied air raids, a godsend which gave us some time to rest in bomb shelters.”

Mother and daughter remained in Ham-burg until April 1945, Sala never letting Renee out of her sight. Says Kate: “It was Sala’s constant presence, her hand in Renee’s, that gave her that all important ingredient for survival: hope.”

But shortly before the war’s end, in April, Sala and Renee were sent to different work sites near the docks.

Renee recalls: “At the end of the day my mother was offloaded from the train on a stretcher. Her mouth and cheek had been ripped open, she was
in so much pain. I was told she had been working near a slaughterhouse and ‘for fun’ a bull had been let out. My poor gentle mama attacked by a bull. To think of her trampled and torn, there was such wickedness and evil and she lost so much strength.”

Finally, the Allied advance got too close for the Germans to ignore and, in April 1945, Renee and her injured mother were transported to Bergen-Belsen.

“It’s just impossible to describe the scenes there with skeletons walking,” Renee remembers. “I was so terrified. I held my mother’s hand in mine, hoping it would give her the strength to hold on. Her voice barely above a whisper, she told me, ‘Do not cry when I die’.”

Twelve days after the British Army liberated Bergen-Belsen on April 15, 1945, Sala succumbed to her injuries and died. Motherhood had given her the will to survive until her daughter was safe. “I didn’t cry, not then. I felt destroyed. My heart was crying, but my eyes were dry,” says Renee.

After the war she found love with Charles Salt, a British military policeman who was involved in the liberation of Bergen-Belsen.

“We never spoke very much about the conditions in which I lost my mother. We didn’t need to. He had seen it for himself.”

Their marriage lasted 62 years until his death in December 2011. During the course of writing her book, Renee discovered her father hadn’t died in the gas chambers in Auschwitz-Birkenau, but a concentration camp in Bavaria called Kaufering, weeks before it was liberated by the Americans.

“After 80 years, I finally know what happened to my father after we were ripped apart at Auschwitz. I have closure. Kate took a memorial plaque to Germany and it was put in the place he is buried.”

As for her mother, Renee’s devotion remains as strong today as it ever did. “I will never forget Mama, or stop speaking her name, for she showed me the most powerful and pure love there is.”

A love without limits.

A Mother’s Promise by Renee Salt with Kate Thompson (Orion, £20) is out now