A political journalist and “lifelong Labour voter” has said she is leaving the party, saying to remain would be to tolerate antisemitism.

In a column in The Times, Jane Merrick, the former political editor of the Independent on Sunday said she would not vote Labour again until there was a new leader who “undoes the damage Corbyn has inflicted”.

Ms Merrick said she had previously decided to stick with the party despite “moments of despair and alarm”, particularly at the party’s handling of the issue of antisemitism.

But after “hovering” over her membership card earlier this year, she said: “I cannot wait any longer. It is not enough to do nothing.”

She could not, she said, “support a party which does not accept the internationally recognised definition of antisemitism, which allows — by omission from this international definition — a member to call a Jewish person a Nazi, or to accuse a Jewish person of being more loyal to Israel than to their home country, or to claim that Israel’s very existence is a racist endeavour.”

She said she understood why Labour MP Dame Margaret Hodge had rounded on Mr Corbyn this week, calling him “an antisemite and racist” to his face in the House of Commons.

“With its heavily qualified definition, Labour’s ruling national executive has officially sanctioned antisemitism. And Corbyn is the leader,” Ms Merrick wrote.

“Yet, instead of supporting and reaching out to Hodge, Labour officials have threatened the former minister with disciplinary action. This disgraceful response shows the scale of the blindspot on this issue.”

Ms Merrick was among the women named as Time Magazine’s Person Of The Year for their efforts to expose sexual harassment.

Michael Fallon resigned as defence secretary after he was revealed to be the MP who had lunged at her trying to kiss her when she was a young political correspondent in 2003.