The company behind Choco Leibniz has apologised for not confronting its “uncomfortable and painful” history of forced labour in Nazi Germany.

A study published this week revealed the extent of forced labour in Bahlsen’s history was worse than previously throught – which prompted the apology. The company employed close to 800 forced labourers, from 1940 to 1945.

The Bahlsen family, who produce the much-loved biscuit, have expressed regret that they “didn’t confront this difficult truth before now”. “We as a family did not pose the obvious question of how our company was able to get through World War II,” they said in a statement.

The company, which sells its products in more than 80 countries around the world, was founded at the end of the 19th century and used forced labour to produce rations for German soldiers. “Our ancestors took advantage of the system in the Nazi period,” the Bahlsen family said. They called the behaviour “unforgivable”.

The study was commissioned by the Bahlsen family after Verena Bahlsen – the great-grandaughter of Choco Leibniz creator Hermann Bahlsen – was accused of minimising the company’s history of forced labour.

The biscuit heiress told Bild in 2019 that the company “did nothing wrong”. “We paid the forced labourers as much as the German and treated them well,” she said. Verena Bahlsen was criticised at the time, with one expert on the period saying the heiress “ignores the fact that forced labourers from Eastern Europe had to live in barracks behind barbed wire”.

Verena Bahlsen apologised, saying “Nothing could be further from me than to downplay National Socialism and its consequences”.

Bahlsen, whose annual sales sit in the region of £450 million, also released a statement. It said the company was “aware of the great suffering and injustice that forced labourers as well as many other people had experienced” and that it recognised “its historical and moral responsibility”. The report was commissioned, and Verena Bahlsen left the company last year.

The forced labourers who worked at Bahlsen were mostly from Nazi-occipied Poland and Ukraine. Mostly women, they were forcibly taken from their homes and sent by cattle car to the Bahlsen factory near Hanover.

Around 26 million people, including Jews, Roma and people of Slavic origin, were used by the Nazis as slave labour during the Second World War.