According to journalist Charles Moore, whose biography of Baroness Thatcher will be released only after her death, the former PM considered Jewish values and Conservatism "a natural fit".
Her support for Jewish causes derived, he says, from her interactions as MP for Finchley with Jewish people.
He also suggests that, as a Methodist, she drew her "raw political and social lessons from the Bible", and emphasised the influence of Edith Muhlbauer, an Austrian Jewish teenager who, in 1938, stayed with the Roberts family in Grantham, after escaping Nazi persecution.
"It had a significant impact," says Mr Moore. "Edith was probably the first Jew she knew in the personal sense."
Twenty years later, campaigning in Finchley, she infuriated local Conservatives by standing with the Liberals to fight a golf club's exclusion of Jews.
Mr Moore says Baroness Thatcher believed that "the Jews were setting a good example. She liked the Jewish approach to looking out for your neighbours, being practical about money, working hard and being family-minded".
Mr Moore says she was frequently irritated by Anglican leaders "lecturing her on state-ist socialist type solutions to everything. She found people like Chief Rabbi Immanuel Jakobovits more congenial in their way of thinking."
He adds: "The mind-set in Europe now, including Britain, tends to see Israel as basically a problem. She saw it as a good thing - her instinct all the way through was 'thank God Israel is there and we must support' it, rather than 'oh, bloody Israel'."