She could be described as one of the first #MeToo victims — an intelligent young woman maltreated by a powerful boss and then dismissed as a “blonde floozy” when his career was threatened.

But the desire for truth in what has been hailed as a new era of transparency about the abuse and marginalisation of women has its limits, as the makers of the controversial new Hollywood film Chappaquiddick have discovered.

Even after almost half a century, associates of the Kennedy family sought to suppress the story of Mary Jo Kopechne, who was left to die in an Oldsmobile that Senator Ted Kennedy had driven off a bridge at Chappaquiddick Island, Massachusetts, in 1969. He then fled the scene.

It happened after a summer party at which Kennedy and five other married men entertained six single women — the so-called “boiler-room girls” — who had worked on the presidential campaign of his brother, Bobby, the previous year.

Kennedy, then 37, did not report the car accident until 10 hours later. He never fully explained why he was with Kopechne, 28, and the film depicts how a team of nine men worked cynically to fix matters so the scion’s political career could be salvaged.

Kopechne is played by Kate Mara, who starred in the American television drama House of Cards. Ironically, she portrayed a character murdered by a top Democratic member of Congress, Frank Underwood, who pushed her in front of a train.

Underwood was played by Kevin Spacey, whose alleged sexual advances towards young men led to him becoming one of the most prominent scalps claimed by the #MeToo campaign.

John Curran, director of Chappaquiddick, told The Sunday Times: “I was worried she’d be afraid of playing another woman killed by a senator.”

Curran, who describes himself as "a liberal Democrat", said he made the film in part because of Donald Trump’s successful presidential campaign.

“I felt disgusted by what was happening on the right and their support for this character running for president,” he said. “But I recognised my own hypocrisy in having a very convenient blind spot to Ted in regard to this story. It’s just empty to keep shouting at the other side and not be prepared to take a hard look at your own candidates.

“This is a story that happened 50 years ago and the fact this is a sacred cow we should not speak about was odd to me, and in itself became a motivating factor. I was angry we weren’t allowed to confront the truth.”

Byron Allen, the film’s executive producer, told Variety magazine “some very powerful people . . . tried to put pressure on me not to release this movie”.

Curran said Chris Dodd, a top Hollywood executive and former Democratic senator for Connecticut, had tried to intervene. Dodd, a one-time drinking friend of Kennedy, last year stepped down as head of the Motion Picture Association of America, a lobbying group for the six biggest studios.

In some respects, Chappaquiddick paints Kennedy as a sympathetic figure, bullied by his domineering father, Joseph, who was determined he should run for president in 1972.

He is shown still to be devastated by the murder of his brother Bobby in 1968, which followed the assassination in 1963 of their sibling, President John F Kennedy. Yet he is also depicted as a shallow, weak and entitled man, more concerned about his own political career than the life of a young woman.

In the movie, his first words after the accident are: “I’m not going to be president.” While that proved to be the case, he still had a distinguished political career and had been a senator for 46 years when he died of a brain tumour in 2009.

Most reviews have praised the film as nuanced and sticking to the documented facts. There is also no conjecture about a sexual relationship with Kopechne. Yet it has been slammed by representatives of the Kennedy family.

Bob Shrum, a former speechwriter for Ted Kennedy, has accused the film makers of “trafficking in conspiracy theories” that did “a disservice both to the victim and the truth”.

Curran responded: “I don’t care what any Kennedy spokesman says, there’s no good version of this story that validates Ted’s behaviour.” The director was determined Kopechne would not be just “an afterthought, or the blonde she was relegated to in history”.

He said: “I was adamant that we knew her ambitions, her closeness to Bobby. I thought it was very important that people recognised that she was a smart, well-educated, ambitious, somewhat square kind of girl.”

A disturbing aspect, he added, was that the five surviving boiler-room girls had not broken ranks to provide a full account of what happened. One, Esther Newberg, contacted the film makers to demand her name be removed.

Referring to Harvey Weinstein, the disgraced Hollywood mogul whose belatedly unmasked depravity triggered the #MeToo movement, Curran added: “As an analogy, if all the women who worked under Weinstein just kept sticking to ‘He’s innocent’, imagine the outrage in light of the evidence contradicting that. To me, it’s sad, but I get it on some level.”

The Kennedys remain a powerful force, he pointed out. “I guess it’s the equivalent in the UK to the royal family. There’s something about that in America even today. From the Kardashians to the Trumps to the Clintons, we seem to embrace families as some kind of idealised version of ourselves.”