LONDON (AP) — A longtime U.K. Labour legislator has left the opposition party and warned that leader Jeremy Corbyn is unfit to become prime minister.

Louise Ellman said Thursday she is leaving the party after 55 years because of Corbyn's failure to confront mounting anti-Semitism in its ranks.

The 73-year-old Jewish legislator said she was "deeply troubled" by spreading anti-Semitism within the Labour Party and felt she had to take a stand with a national election expected in the coming months.

Ellman said that "under Jeremy Corbyn's leadership, anti-Semitism has become mainstream in the Labour Party. Jewish members have been bullied, abused and driven out."

Corbyn has long said there is no place for anti-Semitism in the party but critics say he has done nothing to squelch it.