Labour have launched an investigation into an alleged cover-up after an activist claimed she was told by a party official not to report a rape.
Bex Bailey, 25, who previously served on Labour's ruling National Executive Committee, has revealed she was raped at the age of 19 by someone senior to her in the party who was not an MP.
She claims she was told by the official that if she reported the incident it would be "damaging to her career" and was advised not to take any further action.
Speaking to the BBC Ms Bailey, revealed that she received no support following her ordeal and "wasn't even offered a cup of tea".
Ms Bailey said she opened up about the incident in a bid to achieve "actual change" in the handling of sexual assault cases mid an escalating sexual harassment scandal in Westminster.
The reports of a possible cover up have been met with shock and support for Ms Bailey.
Party leader Jeremy Corbyn said: "Speaking out about rape and sexual harassment takes enormous courage. Bex Bailey has shown incredible bravery by talking publicly about what has happened to her and has my full support and solidarity."
'No tolerance in the Labour Party for sexism, harassment or abuse'
He said that Labour have responded by launching an independent investigation into her claims that she was discouraged from speaking up about the attack at the time of the incident.
"I have asked Labour's general secretary, Iain McNicol, to launch an independent investigation into the allegations that she wasn't given the support from the party she should have received and had the right to expect," said Corbyn.
"There will be no tolerance in the Labour Party for sexism, harassment or abuse. Whatever it takes, we are absolutely committed to rooting it out."
A Labour spokesperson added the party is taking the allegations "extremely seriously" and are encouraging police to investigate the claims of criminality.
Ed Miliband, who was Labour leader at the time of Ms Bailey's alleged rape in 2011, said he was "shocked" by the "horrific allegations".
He wrote on Twitter: "She is showing great bravery and courage in speaking out. Victims must be supported when they come forward. These allegations must be properly investigated by the police and the Labour Party."
Dawn Butler, Labour's shadow women and equalities secretary, was among several MP's who took to social media to praise Ms Bailey for her courage in speaking up, while calling for new measures to be mplemented to ensure that no other woman in the party should suffer any such ordeal again.
Describing Ms Bailey as "a strong and amazing young lady" she said: "The Labour Party is extremely serious about tackling any form of abuse and making sure we have a transparent structure in place," she said.
The inquiry comes after explosive sexual allegations against 36 sitting Conservative MPs were revealed in a spreadsheet put together by Tory aides. The allegations are the latest episode in a sexual harassment scandal that has rocked Westminster.