London (CNN) A new schism opened up in British politics on Monday when seven lawmakers staged a dramatic walkout from Britain's opposition Labour Party, denouncing its handling of a wave of anti-Semitism and a "betrayal" on Brexit.

The seven Members of Parliament, many of them longstanding figures in the party, said variously that Labour was racist, had betrayed its working-class roots and was a threat to national security. Its leader, Jeremy Corbyn, was not fit to become Prime Minister, they said.

One of the seven, Luciana Berger, said she had become ashamed of the party she'd served as a Member of Parliament since 2010. It had become "hijacked by the machine politics of the hard left," she said.

The split reflects the mounting frustration over Labour leader Corbyn's handling of Britain's withdrawal from the European Union, and his alleged failure to deal with the anti-Semitism crisis that has engulfed the party.

Berger was joined by Chuka Umunna, Chris Leslie, Angela Smith, Gavin Shuker and Mike Gapes, who said that they would sit in the House of Commons as an independent group of MPs. Their defections are a stark demonstration of the fractiousness of British politics with just 39 days left to go before the UK is due to leave the EU, with no deal yet in place.

(L-R) Labour MP's Anne Coffey, Angela Smith, Chris Leslie, Mike Gapes, Luciana Berger, Gavin Shuker and Chuka Umunna announce their resignation from the Labour Party.

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