She said she now acknowledged "how stupid I was and how ignorant I was", and wished she had apologised sooner.
"The truth is that some of the stuff I have since looked at and understood, I didn't know at the time," she said. "The language I used was antisemitic, it was offensive.”
Earlier this year the JC revealed that in August 2014, Ms Shah had also posted a tweet with a link to a blog which claimed Zionism had been used to “groom” Jews to “exert political influence at the highest levels of public office”.
And in July 2014, at the height of the Gaza conflict, Ms Shah posted a link on Facebook to a newspaper poll asking whether Israel had committed war crimes.
She wrote: “The Jews are rallying to the poll.” She then called on people to vote “yes”.
In a post in September that year she appeared to liken Israel’s policies to those of Hitler.
Ms Shah told the BBC: “What I did was I hurt people and the language that was the clear antisemitic language, which I didn't know at the time, was when I said, “the Jews are rallying’."
She said she had previously never come across antisemitism, but after she resigned as an aide to Shadow Chancellor John McDonnell she was forced to question whether she was an antisemite.
“I had to really question my heart of hearts. Yes, I have ignorance, yes everybody has prejudice, subconscious biases, but does that make me antisemitic? And the answer was no, I do not have a hatred of Jewish people."
