Chef Yotam Ottolenghi's grandmother had secret life as a Nazi hunter who trapped Holocaust architect Adolf Eichmann

Israeli-born Ottolenghi's grandmother Yael Posener was part of a team of special agents dedicated to tracking down the Hitler henchman responsible for killing 6m Jews.

Her secret role has emerged in a special exhibition called 'Operation Finale – How to Catch a Nazi' staged by fellow former Mossad operative Avner Avraham in Potsdam, Germany.

Britain's favourite cookbook creator Ottolenghi's family fled Germany in the 1930s as Eichmann put Adolf Hitler's horrifying final solution death camps into action. Now a new exhibition opening at the Potsdam Film Museum on March 27 will show Ottolenghi's gran's role in hunting him down.

Curator Avraham, 59, writes: "Yotam Ottolenghi's grandmother was one of the 71 agents involved in Operation Eichmann."

After the Second World War, Yael Posener, the exhibition reveals, joined Mossad in the newly created Israel state.

Officially she worked as an assistant in the Israeli Foreign Ministry, but in fact Posener worked for Mossad, for 12 years from 1952.

Her top secret team tracked down Eichmann to a hideaway in Argentina from where he was snatched in 1960 by Shin Bet agents and brought to Israel where he was tried and hanged.

Posener's role was to create new identities for the Israeli snatch squad who smuggled a doped Eichmann out of the country with a fake passport.

Avraham explained: "One of the few operations in which her name was mentioned was the operation to kidnap Eichmann. She prepared all the cover stories for the Mossad agents who kidnapped Eichmann and obtained new identity cards for them in their target countries.

"Yael invented cover stories for Mossad agents who were deployed abroad. She studied the agents' special characteristics and created a new, personal identity for them."

Born Charlotte Neumann in Berlin in 1910, she got a doctorate on physics but fled Nazi Germany with husband Ludwig Posener and their three-year-old son Peter to Sweden.

Yotam Ottolenghi's mother Ruth was born there in June 1935 and the family emigrated to Jerusalem in 1938 where the celeb chef was born in 1968.

For decades the chef's family was unaware of Posener's secret life. But in an interview with Focus magazine two years ago he said: "Back then, my parents used to visit my grandparents for lunch every Saturday. And that day, my mum heard my grandmother say to her husband, 'He's on a plane.'

"Later, the radio said, 'The Mossad has arrested Adolf Eichmann!'. It was immediately clear to my mother that grandma had something to do with it."

In 1965, his grandmother moved from the Mossad to the Israeli Ministry of Education. She died in Israel in 1990.

Story: NewsX