The MP for Mitcham and Morden has said there must be a "zero-tolerance" approach to dispelling antisemitism from the Labour party.

On what marks her 43rd year of "treasured membership," Siobhain McDonagh spoke out about an issue that has contributed to nearly a dozen MPs quitting their respective parties to join a breakaway Independent Group.

"It is a true honour to represent Mitcham and Morden in Parliament and it is a privilege to have done so for 22 years," Ms McDonagh said.

"In recent months I have watched in horror as the scourge of anti-Jewish racism has reared its ugly head in the party that I represent.

"There can be no doubt, there must be a zero-tolerance approach in rooting all anti-Semitism from our party."

Former minister Joan Ryan, who chaired Labour Friends of Israel and announced she had quit to join the breakaway party, said Jeremy Corbyn was not fit to be prime minister

Ms McDonagh described the departing MP as "the toughest, kindest and wisest person. A fabulous woman who will not be bullied."

But the representative for Mitcham and Morden added that she would continue to stand up for her community and the people in it.

"I want to make absolutely clear that I have never witnessed anti-Jewish racism within Mitcham and Morden Labour Party and I have always received huge support from my local constituency party," she said.

"I will continue to represent all of those who live in Mitcham and Morden as very best I can.

"I will fight to see the Labour Party oppose all forms of racism and I will stand up for our country and our constituency at a time of such national crisis."

Jeremy Corbyn insisted he was tackling anti-Semitism in Labour following the resignation of eight MPs in protest at his leadership.

"Anti-Semitism has no place whatsoever in any of our political parties, in our lives, in our society," he said at Prime Minister's Questions.

"My own political party takes the strongest action to deal with anti-Semitism wherever it rears its head."