Where Stormy Daniels' testimony leaves the Trump trial

Delving into salacious details of an alleged sexual encounter in a Nevada hotel suite with Donald Trump, adult film star Stormy Daniels provided Manhattan prosecutors with helpful - but sometimes irrelevant - context.

Mr Trump has pleaded not guilty to criminal charges of falsifying business records in relation to a hush-money payment made to Ms Daniels. He also denies having sex with her.

One of the most eagerly awaited witnesses of the trial, her appearance in the Manhattan courthouse Tuesday and Thursday proved dramatic.

But whether her at times long-winded testimony significantly boosted prosecutors' case is unclear.

"She was a very sensational witness. There was a lot of evidence that came out that was wholly irrelevant," said former Manhattan prosecutor Diana Florence.

"But at the end of the day, she adds context to the story."

Taking the stand in a modest look with her hair clipped back, Ms Daniels got off to a rocky start Tuesday.

Her meandering responses to prosecutors prompted criticism from Justice Juan Merchan, who later told the court that some of it "would have been better left unsaid".

Mr Trump, meanwhile, sat hunched over in his seat - his son Eric just two rows behind him - as Ms Daniels aired lurid details about their alleged meeting.

The details included Mr Trump greeting her in silk pyjamas at his hotel suite, and the fact that he did not wear a condom when they had sex.

The testimony prompted Mr Trump's lawyers to lodge two mistrial requests, which Justice Merchan denied. The judge had asked prosecutors to tread carefully when probing the specifics of the alleged sexual encounter.

But ultimately, Ms Florence said, the day in court amounted to a "side show" that had little to do with the heart of the case: whether Mr Trump broke the law by classifying reimbursements for Ms Daniels' hush-money payment as "legal expenses".

BBC News reporters are in the Manhattan courtroom covering the historic first criminal trial of a former US president. You'll find their updates and analysis on the BBC news website and app, and across TV, radio and podcasts.

Prosecutors allege he tried to cover up the hush-money payment to save his 2016 presidential election bid.

"It doesn't really matter whether they had intercourse or not," Ms Florence said, adding that Ms Daniels' testimony "went on too long."

Still, the material made for a tense couple of days in court, including on Thursday, as a defiant Ms Daniels went head-to-head with a forceful Trump attorney, Susan Necheles.

Ms Necheles tried to damage Ms Daniels' credibility by accusing her of making up the alleged sexual encounter.

At one point, Ms Necheles claimed Ms Daniels had made up the story just like the screenplays she wrote for the adult films she starred in.

"The sex in those films was very much real, just like what happened to me in that [hotel] room," a frustrated Ms Daniels responded.

Her response was a "mic drop", said former Manhattan prosecutor Jeremy Saland.

"She hit back hard," he said.

At another point, Ms Necheles accused Ms Daniels of lying about not actually eating dinner at Mr Trump's hotel suite on the night of the alleged sexual encounter.

"Your words don't mean what you say, do they?" she told Ms Daniels.

Ms Daniels stuck to the broad facts of her story.

"You're trying to trick me into saying something that's not entirely true," she told Ms Necheles later on.

Ms Necheles kept swinging, working to portray Ms Daniels as a money-hungry woman who fabricated details.

The strategy may have been too aggressive for a witness who had an "air of truthfulness", Mr Saland said.

"She came across as very strong, and I think the defence did a poor job … in really trying to dehumanise her," he said.

With their cross-examination, Mr Trump's legal team also may have inadvertently helped the prosecution's case, experts said.

While grilling Ms Daniels, the defence demonstrated exactly why Mr Trump would have tried to conceal the sex scandal before the election - to avoid association with a witness the defence team portrayed as ''tawdry,'' Ms Florence said.

"It was a side show at the trial - and it would've been a main event just before the election," she said.

Though Ms Daniels appeared more composed during her second day of cross examination, her testimony at times aired bizarre details about her life.

On one occasion, Ms Necheles - to damage Ms. Daniels' credibility - started pressing her for details on a television show she made about "talking to ghosts".

Ms Daniels explained that the show involved investigating ghosts at her haunted Louisiana home. In the end, though, it was just a "giant opossum that was under the house", she testified.

But the story also veered away from the business records that are key to the case.

Still, Mr Saland said, Ms Daniels' candid answers helped set up Mr Trump's motivation for the reimbursement of the hush money - and his alleged illegal cover up.

"It was valuable in the sense that it builds the narrative and helps us understand how we got here," Mr Saland said.

"It's why Trump paid. She's the vehicle of the story, but she's not the story."

For Ms Daniels, though, coming forward years ago about with the alleged sexual encounter has brought little good to her life, she told the court Thursday.

Asked by prosecutors whether telling her story was a net negative or net positive, she replied in a soft voice: "Negative".