IT’S called The Butterfly Effect - a butterfly flaps its wings in China and causes a hurricane on the other side of the world.

In 2017 it took on a new incarnation, The Weinstein Effect. In the latter part of the last century a movie mogul made his first predatory moves on young actresses, blowing the first faint breath of a global storm that would rage from Hollywood to Holyrood in 2017.

It began as little more than a whisper on the wind. In 1998, actress Gwyneth Paltrow spoke out about Weinstein’s “coercive” behaviour, and seven years later singer Courtney Love warned young starlets to avoid his parties, but these comments were largely overlooked at the time.

By the second decade of the 21st century, it had become something of an unsavoury showbiz in-joke. Weinstein’s “casting couch” behaviour was highlighted a magazine article, a TV sitcom and even the 2013 Oscars when host Seth MacFarlane joked that female nominees no longer had to court Weinstein’s advances.

It was a classic example of the prevailing attitude to sexual harassment for centuries. It could be alluded to, but rarely tackled head on. It has the same “her versus him” confrontational obstacles that see the vast majority of rape allegations fall short of conviction, but with even less corroborating evidence.

That was until October 2017, when dozens of actresses spoke out about their own encounters with Weinstein over the decades.

The sexual harassment allegations stretched back decades and came from actresses, as well as former employees of the Weinstein Company and Miramax, the previous company that Mr Weinstein and his brother Bob founded.

All told similar tales of being on the wrong end of a familiar power dynamic in Hollywood, with Mr Weinstein promising to boost their careers in return for sexual favours.

Two decades ago, actress Ashley Judd, the former wife of Scots racing driver Dario Franchitti, went to the Peninsula Beverly Hills hotel for what the young actress expected to be a business breakfast meeting with Mr Weinstein.

Instead, he had her sent up to his room, where he appeared in a bathrobe and asked if he could give her a massage or she could watch him shower, she recalled in an interview.

"How do I get out of the room as fast as possible without alienating Harvey Weinstein?" Ms Judd told The New York Times.

In 2014, Mr Weinstein invited Emily Nestor, who had worked just one day as a temporary employee, to the same hotel and made another offer: If she accepted his sexual advances, he would boost her career, according to accounts she provided to colleagues who sent them to TWC executives.

The following year, once again at the Peninsula, a female assistant said Mr Weinstein pestered her into giving him a massage while he was naked, leaving her "crying and very distraught", wrote a colleague, Lauren O'Connor, in a memo asserting sexual harassment and other misconduct by their boss which has now come to light.

Among those to catch Mr Weinstein's eye were a young assistant in New York in 1990, an actress in 1997, an assistant in London in 1998, an Italian model in 2015 and Ms O'Connor herself.

According to records and those familiar with the settlements each was paid.

Ms O'Connor said: "I am a 28-year-old woman trying to make a living and a career.

"Harvey Weinstein is a 64-year-old, world-famous man and this is his company. The balance of power is me: 0, Harvey Weinstein: 10."

Weinstein was unceremoniously sacked from his own company within days and his wife turned his back on him.

The mounting allegations inspired an international movement which earned the Twitter hashtag #MeToo as women — and men — from all walks of life spoke out about the harassment they faced from people of influence.

Notable Hollywood stars who have faced allegations of inappropriate behaviour include Kevin Spacey, Steven Seagal, Dustin Hoffman, Oliver Stone, George Takei, James Woods and Richard Dreyfuss.

The hashtag was used millions of times across scores of countries by people indicating that they had been on the receiving end of unwelcome attention.

Notable stars who declared #MeToo included Patricia Arquette, Thora Birch, Björk, Sheryl Crow, Ellen DeGeneres, Lady Gaga, Heather Graham, Monica Lewinsky, Anna Paquin and Reese Witherspoon.

By the end of October, the scandal had reached the ears of politicians at Westminster — but some had still not got the message that sexual harassment is no laughing matter.

UK Environment Secretary Michael Gove claimed that being interviewed by BBC Radio 4 presenter John Humphrys was like "going into Harvey Weinstein's bedroom”, sparking a furious social media backlash and a hasty apology for his “clumsy” joke.

More politicians soon had the smutty grins wiped from their faces, with International Trade Minister Mark Garnier accused of calling his secretary “sugar tits” and sending her to Soho for sex toys. He decided to take the allegations “on the chin” and was cleared of a breach of the ministerial code shortly before Christmas.

While Garnier decided to tough out the Westminster disciplinary process, Defence Secretary Sir Michael Fallon swiftly resigned at the start of November when he was accused of unacceptable behaviour towards women.

In his resignation letter, Fallon said: “I accept that in the past I have fallen below the high standards that we require of the armed forces that I have the honour to represent.”

In an interview, he added: “The culture has changed over the years. What might have been acceptable 15, 10 years ago, is clearly not acceptable now.”

First Secretary of State Damian Green was also sacked shortly before Christmas for "inaccurate and misleading" statements over what he knew about claims pornography was found on his office computer in 2008. Mr Green also apologised for making journalist and Tory activist Kate Maltby feel uncomfortable, following allegations of inappropriate behaviour towards her in 2015.

The Scottish Parliament, which prides itself on its relative gender equality and family friendly business schedule, soon proved that it was not immune from the global outrage.

Scottish human rights lawyer Aamer Anwar said women at all levels of the Scottish Parliament had been sexually harassed.

"It's a catalogue of sexual harassment, stalking, social media abuse, sexual innuendos, verbal sexual abuse, touching, sexual assaults, requests for sex, cover-up, isolation and bullying,” he said.

The parliament set up a harassment hotline and First Minister Nicola Sturgeon made a direct appeal to senior men in the SNP to "reflect on your own behaviour”.

In an internal email, the First Minister urged those "in positions of power" to read what women have been saying and "consider whether any of those instances would ever apply to your past or current behaviour”.

The global scandal claimed its first Holyrood scalp on November 4, when Childcare Minister Mark McDonald resigned amid allegations of inappropriate behaviour.

He said: "It has been brought to my attention that some of my previous actions have been considered to be inappropriate - where I have believed myself to have been merely humorous or attempting to be friendly, my behaviour might have made others uncomfortable or led them to question my intentions.

"My behaviour is entirely my responsibility and I apologise unreservedly to anyone I have upset or who might have found my behaviour inappropriate.”

SNP councillor Jordan Linden stepped down from North Lanarkshire Council amid allegations that he sent an explicit photograph to a member of the Scottish Youth Parliament and sexually harassed others while he was a member between 2011 and 2016. He has denied the allegation and continues to be employed by SNP MSP Richard Lyle.

Labour MSP Monica Lennon said that she was groped by a senior figure in the party.

The Central Scotland MSP told how the man touched her "in a manner that some would say is 'handsy'".

"He was sitting next to me when he groped me, in full view of other people. He touched my body, in an intimate way, without invitation or permission,” she said.

"It's possible at least half a dozen people saw exactly what happened.

"One man, who at the time was a Labour politician, joked to everyone in earshot, 'That's your fault for coming over here and getting him all excited’.”

It was a familiar pattern seen throughout the years of when The Weinstein Effect was nothing but a whisper. Grope first, laugh next, apologise last. Nobody is laughing now.