Image copyright Getty Images Image caption Joe Biden's campaign has denied the new allegations against him

Former Vice-President Joe Biden has denied an allegation that he sexually assaulted a former aide nearly 30 years ago as a US senator.

Tara Reade, who worked briefly as a staff assistant in Mr Biden's office, has said that her former boss forced her against a wall, putting his hands under her shirt and skirt.

"This absolutely did not happen," Mr Biden's campaign said this week.

Mr Biden, 77, is now the presumptive Democratic nominee for president.

"He firmly believes that women have a right to be heard - and heard respectfully," said his campaign spokeswoman. "Such claims should also be diligently reviewed by an independent press. What is clear about this claim: It is untrue."

Ms Reade, 56, described the allegation in an interview with podcast host Katie Halper in March.

She was asked to deliver a gym bag to the senator in the spring of 1993, she said, and found herself alone with Mr Biden.

"There was no exchange, really, he just had me up against the wall," she said to Ms Halper.

"I remember it happened all at once... his hands were on me and underneath my clothes." He then penetrated her with his fingers, she said.

"I remember him saying, first, as he was doing it 'Do you want to go somewhere else?' and then him saying to me, when I pulled away... he said 'Come on man, I heard you liked me,'" she said. "That phrase stayed with me."

The fact he was a champion of women's rights in her eyes made the experience all the more shattering, she said.

Image copyright Getty Images Image caption Then-Senator Biden at the 1991 confirmation hearing for Supreme Court Justice Clarence Thomas

Ms Reade filed a criminal complaint on 9 April with police, saying she was a victim of sexual assault but did not name Mr Biden. She said in a tweet that she filed the complained "for safety reasons only", as the statute of limitations for her claim have expired.

Ms Reade was one of eight women who came forward last year to accuse the candidate of inappropriate touching, hugging or kissing, though none described his actions as sexual assault at the time.

In response, Mr Biden pledged to be "more mindful" in his interactions.

Will this hurt Biden's presidential bid? Probably not

It's possible that Tara Reade's accusation of sexual assault against Joe Biden could derail his campaign, but it seems unlikely. Here's why.

Americans already know about the "touchy feely-ness" of the former Vice President and they factored that in as they chose him to be their nominee. He put out a video saying he'd learned from #metoo that times have changed and that his history of rubbing women's shoulders, kissing their heads etc was not appropriate. Evidently, that was seen as apology enough by most primary voters.

An accusation of sexual assault is of course more serious but the criteria for judging whether someone is a sexual abuser is looking at a consistent story from the accuser and a pattern of behaviour in the accused. Ms Reade told different versions of her story to the New York Times and so far she is the only woman to accuse Biden of sexual assault. If no others emerge, Democrats may be inclined to believe their candidate over her.

Joe Biden is running against Donald Trump, who has been accused of sexual misconduct by some 25 women. That may not stop the President using it as an attack line (he's hinted at it before,) but it does diminish the credibility of the attack.

In the midst of this pandemic, almost no other news is breaking through. In a normal cycle this story would be getting a lot more attention in newspaper headlines and on cable TV. Today it barely registers. That's helpful for Biden.

The Democratic Party does hold itself to a higher standard on inclusivity of race and gender than the Republican Party does, so this accusation is uncomfortable. But this year, the standard that matters most to Democrats is getting Trump out of the White House. They believe Biden has the best shot at doing that.

In an investigation into Ms Reade's account by the New York Times, two friends and Ms Reade's brother said she described the details of a traumatic sexual attack involving the former vice-president.

But the newspaper found no corroboration from any former staff members of Mr Biden and found "no pattern of sexual misconduct by Mr Biden".

Ms Reade said she reported harassment by Mr Biden - without mentioning the alleged assault - to several senior members of Mr Biden's staff, including Mr Biden's executive assistant, Marianne Baker.

Ms Baker denies ever hearing such a complaint.

"I have absolutely no knowledge or memory of Ms Reade's accounting of events, which would have left a searing impression on me as a woman professional, and as a manager."

Media playback is unsupported on your device Media caption Joe Biden addresses 'touch-feely' allegations against him in 2019

After the staff declined to respond to her reports of harassment, Ms Reade says she filed a complaint with the Senate. No record of a complaint has been located. Soon after, Ms Reade said office staff took away most of her duties before ultimately dismissing her.

Ms Reade has since moved to the US West Coast where she has worked for a state senator, an advocate for domestic assault survivors and for animal rescue organisations.

The allegations have surfaced just as Senator Bernie Sanders has quit the White House race, making Mr Biden, in all likelihood, the Democratic nominee for president. He is expected to take on Donald Trump in the US election in November.